From 313be43493606c920b2a5181b7fb09621c8e0f04 Mon Sep 17 00:00:00 2001
From: Sara Gerion <47529391+saragerion@users.noreply.github.com>
Date: Thu, 30 Dec 2021 20:49:16 +0100
Subject: [PATCH 01/12] docs(logger): WIP jsdocs Logger.ts

---
 .eslintrc.js                  |   2 +-
 packages/logger/src/Logger.ts | 134 ++++++++++++++++++++++++++++++++++
 2 files changed, 135 insertions(+), 1 deletion(-)

diff --git a/.eslintrc.js b/.eslintrc.js
index b83ce24ffc..a8cbf8ceef 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -7,7 +7,7 @@ module.exports = {
   },
   extends: [ 'plugin:@typescript-eslint/eslint-recommended', 'plugin:@typescript-eslint/recommended' ],
   parser: '@typescript-eslint/parser',
-  plugins: ['@typescript-eslint'],
+  plugins: ['@typescript-eslint', 'jsdoc'],
   settings: {
     'import/resolver': {
       node: {},
diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
index caf980eb7c..27ce6f61d3 100644
--- a/packages/logger/src/Logger.ts
+++ b/packages/logger/src/Logger.ts
@@ -17,6 +17,27 @@ import type {
   PowertoolLogData,
 } from './types';
 
+/**
+ * ## Intro
+ *
+ * Logger provides an opinionated logger with output structured as JSON.
+ *
+ * ## Key features
+ *
+ * - Capture key fields from Lambda context, cold start and structures logging output as JSON
+ * - Log Lambda context when instructed (disabled by default)
+ * - Log sampling prints all logs for a percentage of invocations (disabled by default)
+ * - Append additional keys to structured log at any point in time
+ *
+ * ## Usage
+ *
+ * import { Logger } from "@aws-lambda-powertools/logger";
+ * const logger = new Logger();
+ *
+ * @class
+ * @implements {ClassThatLogs}
+ * @see https://awslabs.github.io/aws-lambda-powertools-typescript/latest/core/logger/
+ */
 class Logger implements ClassThatLogs {
 
   private static coldStart?: boolean = undefined;
@@ -48,10 +69,28 @@ class Logger implements ClassThatLogs {
 
   private powertoolLogData: PowertoolLogData = <PowertoolLogData>{};
 
+  /**
+   * It takes a set of options (settings):
+   *   - logging level
+   *   - name of the service
+   *   - sample rate value
+   *   - log formatter
+   *   - config service
+   *   - persistent attributes
+   *   - environment name
+   * @param {LoggerOptions} options
+   */
   public constructor(options: LoggerOptions = {}) {
     this.setOptions(options);
   }
 
+  /**
+   * Adds the current AWS Lambda's invocation context data to the powertoolLogData propriety of the instance.
+   * This context data will be part of all printed log items.
+   *
+   * @param {Context} context
+   * @return {void}
+   */
   public addContext(context: Context): void {
     Logger.evaluateColdStartOnce();
     const lambdaContext: Partial<LambdaFunctionContext> = {
@@ -68,18 +107,42 @@ class Logger implements ClassThatLogs {
     });
   }
 
+  /**
+   * Adds given attributes (key-value pairs) to all log items generated by this Logger instance.
+   *
+   * @param {LogAttributes} attributes
+   * @return {void}
+   */
   public addPersistentLogAttributes(attributes?: LogAttributes): void {
     this.persistentLogAttributes = merge(this.getPersistentLogAttributes(), attributes);
   }
 
+  /**
+   * Alias for addPersistentLogAttributes.
+   *
+   * @param {LogAttributes} attributes
+   * @return {void}
+   */
   public appendKeys(attributes?: LogAttributes): void {
     this.addPersistentLogAttributes(attributes);
   }
 
+  /**
+   * Creates a separated Logger instance, identical to the current one.
+   * It's possible to overwrite the new instance options by passing them.
+   *
+   * @param {LoggerOptions} options
+   * @returns {Logger}
+   */
   public createChild(options: LoggerOptions = {}): Logger {
     return cloneDeep(this).setOptions(options);
   }
 
+  /**
+   *
+   * @param {LogItemMessage} input
+   * @param {Error | LogAttributes | unknown} extraInput
+   */
   public debug(input: LogItemMessage, ...extraInput: LogItemExtraInput): void {
     if (!this.shouldPrint('DEBUG')) {
       return;
@@ -87,28 +150,53 @@ class Logger implements ClassThatLogs {
     this.printLog(this.createAndPopulateLogItem('DEBUG', input, extraInput));
   }
 
+  /**
+   *
+   * @param {LogItemMessage} input
+   * @param {Error | LogAttributes | unknown} extraInput
+   */
   public error(input: LogItemMessage, ...extraInput: LogItemExtraInput): void {
     this.printLog(this.createAndPopulateLogItem('ERROR', input, extraInput));
   }
 
+  /**
+   *
+   */
   public static evaluateColdStartOnce(): void {
     if (Logger.getColdStartEvaluatedValue() === false) {
       Logger.evaluateColdStart();
     }
   }
 
+  /**
+   *
+   * @returns {boolean}
+   */
   public static getColdStartEvaluatedValue(): boolean {
     return Logger.coldStartEvaluated;
   }
 
+  /**
+   *
+   * @returns {boolean | undefined}
+   */
   public static getColdStartValue(): boolean | undefined {
     return Logger.coldStart;
   }
 
+  /**
+   *
+   * @returns {boolean}
+   */
   public getLogsSampled(): boolean {
     return this.logsSampled;
   }
 
+  /**
+   *
+   * @param {LogItemMessage} input
+   * @param {Error | LogAttributes | unknown} extraInput
+   */
   public info(input: LogItemMessage, ...extraInput: LogItemExtraInput): void {
     if (!this.shouldPrint('INFO')) {
       return;
@@ -116,6 +204,10 @@ class Logger implements ClassThatLogs {
     this.printLog(this.createAndPopulateLogItem('INFO', input, extraInput));
   }
 
+  /**
+   *
+   * @returns {HandlerMethodDecorator}
+   */
   public injectLambdaContext(): HandlerMethodDecorator {
     return (target, propertyKey, descriptor) => {
       const originalMethod = descriptor.value;
@@ -129,18 +221,33 @@ class Logger implements ClassThatLogs {
     };
   }
 
+  /**
+   *
+   */
   public refreshSampleRateCalculation(): void {
     this.setLogsSampled();
   }
 
+  /**
+   *
+   * @param {boolean} value
+   */
   public static setColdStartEvaluatedValue(value: boolean): void {
     Logger.coldStartEvaluated = value;
   }
 
+  /**
+   *
+   * @param {boolean | undefined} value
+   */
   public static setColdStartValue(value: boolean | undefined): void {
     Logger.coldStart = value;
   }
 
+  /**
+   *
+   * @param {number} sampleRateValue
+   */
   public setSampleRateValue(sampleRateValue?: number): void {
     this.powertoolLogData.sampleRateValue =
       sampleRateValue ||
@@ -148,6 +255,11 @@ class Logger implements ClassThatLogs {
       this.getEnvVarsService().getSampleRateValue();
   }
 
+  /**
+   *
+   * @param {LogItemMessage} input
+   * @param {Error | LogAttributes | unknown} extraInput
+   */
   public warn(input: LogItemMessage, ...extraInput: LogItemExtraInput): void {
     if (!this.shouldPrint('WARN')) {
       return;
@@ -155,12 +267,25 @@ class Logger implements ClassThatLogs {
     this.printLog(this.createAndPopulateLogItem('WARN', input, extraInput));
   }
 
+  /**
+   *
+   * @param {Partial<PowertoolLogData>} attributesArray
+   * @private
+   */
   private addToPowertoolLogData(...attributesArray: Array<Partial<PowertoolLogData>>): void {
     attributesArray.forEach((attributes: Partial<PowertoolLogData>) => {
       this.powertoolLogData = merge(this.getPowertoolLogData(), attributes);
     });
   }
 
+  /**
+   *
+   * @param {LogLevel} logLevel
+   * @param {LogItemMessage} input
+   * @param {LogItemExtraInput} extraInput
+   * @returns {LogItem}
+   * @private
+   */
   private createAndPopulateLogItem(logLevel: LogLevel, input: LogItemMessage, extraInput: LogItemExtraInput): LogItem {
     const unformattedBaseAttributes = merge(this.getPowertoolLogData(), {
       logLevel,
@@ -185,6 +310,10 @@ class Logger implements ClassThatLogs {
     return logItem;
   }
 
+  /**
+   *
+   * @private
+   */
   private static evaluateColdStart(): void {
     const coldStartValue = Logger.getColdStartValue();
     if (typeof coldStartValue === 'undefined') {
@@ -198,6 +327,11 @@ class Logger implements ClassThatLogs {
     Logger.setColdStartEvaluatedValue(true);
   }
 
+  /**
+   *
+   * @returns {ConfigServiceInterface | undefined}
+   * @private
+   */
   private getCustomConfigService(): ConfigServiceInterface | undefined {
     return this.customConfigService;
   }

From 57c5929b198e51e796d6a3d37d982493375b8f66 Mon Sep 17 00:00:00 2001
From: Sara Gerion <sgerion@amazon.com>
Date: Wed, 19 Jan 2022 21:54:30 +0100
Subject: [PATCH 02/12] feat(logger): add jsdocs support

---
 packages/logger/src/Logger.ts                 | 213 ++++++++++++++++--
 packages/logger/src/config/ConfigService.ts   |  43 +++-
 .../src/config/ConfigServiceInterface.ts      |  33 +++
 .../src/config/EnvironmentVariablesService.ts |  64 ++++++
 packages/logger/src/formatter/LogFormatter.ts |  33 +++
 .../src/formatter/LogFormatterInterface.ts    |  17 ++
 .../src/formatter/PowertoolLogFormatter.ts    |  13 ++
 packages/logger/src/middleware/middy.ts       |   7 +
 8 files changed, 403 insertions(+), 20 deletions(-)

diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
index dd57dfc706..4ac0faa269 100644
--- a/packages/logger/src/Logger.ts
+++ b/packages/logger/src/Logger.ts
@@ -19,9 +19,12 @@ import type {
 } from './types';
 
 /**
+ *
+ * # Logger class
+ *
  * ## Intro
  *
- * Logger provides an opinionated logger with output structured as JSON.
+ * The Logger utility provides an opinionated logger with output structured as JSON.
  *
  * ## Key features
  *
@@ -30,7 +33,7 @@ import type {
  * - Log sampling prints all logs for a percentage of invocations (disabled by default)
  * - Append additional keys to structured log at any point in time
  *
- * ## Usage
+ * ## Basic usage
  *
  * import { Logger } from "@aws-lambda-powertools/logger";
  * const logger = new Logger();
@@ -41,6 +44,10 @@ import type {
  */
 class Logger implements ClassThatLogs {
 
+  /**
+   *
+   * @private
+   */
   private static coldStart?: boolean = undefined;
 
   private static coldStartEvaluated: boolean = false;
@@ -71,14 +78,8 @@ class Logger implements ClassThatLogs {
   private powertoolLogData: PowertoolLogData = <PowertoolLogData>{};
 
   /**
-   * It takes a set of options (settings):
-   *   - logging level
-   *   - name of the service
-   *   - sample rate value
-   *   - log formatter
-   *   - config service
-   *   - persistent attributes
-   *   - environment name
+   * It initializes the Logger class with an optional set of options (settings).
+   * *
    * @param {LoggerOptions} options
    */
   public constructor(options: LoggerOptions = {}) {
@@ -90,7 +91,7 @@ class Logger implements ClassThatLogs {
    * This context data will be part of all printed log items.
    *
    * @param {Context} context
-   * @return {void}
+   * @returns {void}
    */
   public addContext(context: Context): void {
     Logger.evaluateColdStartOnce();
@@ -112,7 +113,7 @@ class Logger implements ClassThatLogs {
    * Adds given attributes (key-value pairs) to all log items generated by this Logger instance.
    *
    * @param {LogAttributes} attributes
-   * @return {void}
+   * @returns {void}
    */
   public addPersistentLogAttributes(attributes?: LogAttributes): void {
     this.persistentLogAttributes = merge(attributes, this.getPersistentLogAttributes());
@@ -122,14 +123,14 @@ class Logger implements ClassThatLogs {
    * Alias for addPersistentLogAttributes.
    *
    * @param {LogAttributes} attributes
-   * @return {void}
+   * @returns {void}
    */
   public appendKeys(attributes?: LogAttributes): void {
     this.addPersistentLogAttributes(attributes);
   }
 
   /**
-   * Creates a separated Logger instance, identical to the current one.
+   * Creates a separate Logger instance, identical to the current one.
    * It's possible to overwrite the new instance options by passing them.
    *
    * @param {LoggerOptions} options
@@ -140,25 +141,32 @@ class Logger implements ClassThatLogs {
   }
 
   /**
+   * It prints a log item with level DEBUG.
    *
    * @param {LogItemMessage} input
    * @param {Error | LogAttributes | unknown} extraInput
+   * @returns {void}
    */
   public debug(input: LogItemMessage, ...extraInput: LogItemExtraInput): void {
     this.processLogItem('DEBUG', input, extraInput);
   }
 
   /**
+   * It prints a log item with level ERROR.
    *
    * @param {LogItemMessage} input
    * @param {Error | LogAttributes | unknown} extraInput
+   * @returns {void}
    */
   public error(input: LogItemMessage, ...extraInput: LogItemExtraInput): void {
     this.processLogItem('ERROR', input, extraInput);
   }
 
   /**
+   * It evaluates whether the current Lambda function invocation has a cold start or not.
    *
+   * @static
+   * @returns {void}
    */
   public static evaluateColdStartOnce(): void {
     if (!Logger.getColdStartEvaluatedValue()) {
@@ -167,7 +175,10 @@ class Logger implements ClassThatLogs {
   }
 
   /**
+   * It returns a boolean true value if the current Lambda function invocation has been already evaluated to
+   * determine if it's a cold start, false if not.
    *
+   * @static
    * @returns {boolean}
    */
   public static getColdStartEvaluatedValue(): boolean {
@@ -175,7 +186,9 @@ class Logger implements ClassThatLogs {
   }
 
   /**
+   * It returns a boolean true value if the current Lambda function invocation has a cold start, false otherwise.
    *
+   * @static
    * @returns {boolean | undefined}
    */
   public static getColdStartValue(): boolean | undefined {
@@ -183,6 +196,8 @@ class Logger implements ClassThatLogs {
   }
 
   /**
+   * It returns a boolean true value if, in case of sample rating feature enabled, the current
+   * Lambda function invocation's logs will be printed to stdout. It returns false otherwise.
    *
    * @returns {boolean}
    */
@@ -191,16 +206,23 @@ class Logger implements ClassThatLogs {
   }
 
   /**
+   * It prints a log item with level INFO.
    *
    * @param {LogItemMessage} input
    * @param {Error | LogAttributes | unknown} extraInput
+   * @returns {void}
    */
   public info(input: LogItemMessage, ...extraInput: LogItemExtraInput): void {
     this.processLogItem('INFO', input, extraInput);
   }
 
   /**
+   * Method decorator that adds the current Lambda function context as extra
+   * information in all log items.
+   * The decorator can be used only when attached to a Lambda function handler which
+   * is written as method of a class, and should be declared just before the handler declaration.
    *
+   * @see https://www.typescriptlang.org/docs/handbook/decorators.html#method-decorators
    * @returns {HandlerMethodDecorator}
    */
   public injectLambdaContext(): HandlerMethodDecorator {
@@ -216,31 +238,46 @@ class Logger implements ClassThatLogs {
   }
 
   /**
+   * If the sample rate feature is enabled, the calculation that determines whether the logs
+   * will actually be printed or not for this invocation is done when the Logger class is
+   * initialized.
+   * This method will repeat that calculation (with possible different outcome).
    *
+   * @returns {void}
    */
   public refreshSampleRateCalculation(): void {
     this.setLogsSampled();
   }
 
   /**
+   * Sets the value of a flag static propriety that tracks whether
+   * the cold start evaluation already took place.
    *
    * @param {boolean} value
+   * @static
+   * @returns {void}
    */
   public static setColdStartEvaluatedValue(value: boolean): void {
     Logger.coldStartEvaluated = value;
   }
 
   /**
+   * Sets the value of a flag static propriety that tracks whether
+   * the current Lambda invocation experienced a cold start.
    *
    * @param {boolean | undefined} value
+   * @static
+   * @returns {void}
    */
   public static setColdStartValue(value: boolean | undefined): void {
     Logger.coldStart = value;
   }
 
   /**
+   * It sets the user-provided sample rate value.
    *
    * @param {number} sampleRateValue
+   * @returns {void}
    */
   public setSampleRateValue(sampleRateValue?: number): void {
     this.powertoolLogData.sampleRateValue =
@@ -250,18 +287,23 @@ class Logger implements ClassThatLogs {
   }
 
   /**
+   * It prints a log item with level WARN.
    *
    * @param {LogItemMessage} input
    * @param {Error | LogAttributes | unknown} extraInput
+   * @returns {void}
    */
   public warn(input: LogItemMessage, ...extraInput: LogItemExtraInput): void {
     this.processLogItem('WARN', input, extraInput);
   }
 
   /**
+   * Adds information to a class propriety that contains information that
+   * is printed in all log items.
    *
    * @param {Partial<PowertoolLogData>} attributesArray
    * @private
+   * @returns {void}
    */
   private addToPowertoolLogData(...attributesArray: Array<Partial<PowertoolLogData>>): void {
     attributesArray.forEach((attributes: Partial<PowertoolLogData>) => {
@@ -270,14 +312,18 @@ class Logger implements ClassThatLogs {
   }
 
   /**
+   * It processes a particular log item so that it can be printed to stdout:
+   * - Merges ephemeral log attributes with persistent log attributes (printed for all logs) and additional info;
+   * - Formats all the log attributes;
    *
+   * @private
    * @param {LogLevel} logLevel
    * @param {LogItemMessage} input
    * @param {LogItemExtraInput} extraInput
    * @returns {LogItem}
-   * @private
    */
   private createAndPopulateLogItem(logLevel: LogLevel, input: LogItemMessage, extraInput: LogItemExtraInput): LogItem {
+    // TODO: this method's logic is hard to understand, there is an opportunity here to simplify this logic.
     const unformattedBaseAttributes = merge({
       logLevel,
       timestamp: new Date(),
@@ -302,8 +348,12 @@ class Logger implements ClassThatLogs {
   }
 
   /**
+   * It evaluates whether the current Lambda invocation experienced a
+   * cold start.
    *
    * @private
+   * @static
+   * @returns {void}
    */
   private static evaluateColdStart(): void {
     const coldStartValue = Logger.getColdStartValue();
@@ -319,34 +369,74 @@ class Logger implements ClassThatLogs {
   }
 
   /**
+   * It returns the custom config service, an abstraction used to fetch environment variables.
    *
-   * @returns {ConfigServiceInterface | undefined}
    * @private
+   * @returns {ConfigServiceInterface | undefined}
    */
   private getCustomConfigService(): ConfigServiceInterface | undefined {
     return this.customConfigService;
   }
 
+  /**
+   * It returns the instance of a service that fetches environment variables.
+   *
+   * @private
+   * @returns {EnvironmentVariablesService}
+   */
   private getEnvVarsService(): EnvironmentVariablesService {
     return <EnvironmentVariablesService> this.envVarsService;
   }
 
+  /**
+   * It returns the instance of a service that formats the structure of a
+   * log item's keys and values in the desired way.
+   *
+   * @private
+   * @returns {LogFormatterInterface}
+   */
   private getLogFormatter(): LogFormatterInterface {
     return <LogFormatterInterface> this.logFormatter;
   }
 
+  /**
+   * It returns the log level set for the Logger instance.
+   *
+   * @private
+   * @returns {LogLevel}
+   */
   private getLogLevel(): LogLevel {
     return <LogLevel> this.logLevel;
   }
 
+  /**
+   * It returns the persistent log attributes, which are the attributes
+   * that will be logged in all log items.
+   *
+   * @private
+   * @returns {LogAttributes}
+   */
   private getPersistentLogAttributes(): LogAttributes {
     return <LogAttributes> this.persistentLogAttributes;
   }
 
+  /**
+   * It returns information that will be added in all log item by
+   * this Logger instance (different from user-provided persistent attributes).
+   *
+   * @private
+   * @returns {LogAttributes}
+   */
   private getPowertoolLogData(): PowertoolLogData {
     return this.powertoolLogData;
   }
 
+  /**
+   * It returns the numeric sample rate value.
+   *
+   * @private
+   * @returns {number}
+   */
   private getSampleRateValue(): number {
     if (!this.powertoolLogData?.sampleRateValue) {
       this.setSampleRateValue();
@@ -355,10 +445,24 @@ class Logger implements ClassThatLogs {
     return <number> this.powertoolLogData?.sampleRateValue;
   }
 
+  /**
+   * It returns true if the provided log level is valid.
+   *
+   * @param {LogLevel} logLevel
+   * @private
+   * @returns {boolean}
+   */
   private isValidLogLevel(logLevel?: LogLevel): boolean {
     return typeof logLevel === 'string' && logLevel.toUpperCase() in this.logLevelThresholds;
   }
 
+  /**
+   * It prints a given log with given log level.
+   *
+   * @param {LogLevel} logLevel
+   * @param {LogItem} log
+   * @private
+   */
   private printLog(logLevel: LogLevel, log: LogItem): void {
     log.prepareForPrint();
 
@@ -367,6 +471,13 @@ class Logger implements ClassThatLogs {
     console[consoleMethod](JSON.stringify(log.getAttributes(), this.removeCircularDependencies()));
   }
 
+  /**
+   * It prints a given log with given log level.
+   *
+   * @param {LogLevel} logLevel
+   * @param {LogItem} log
+   * @private
+   */
   private processLogItem(logLevel: LogLevel, input: LogItemMessage, extraInput: LogItemExtraInput): void {
     if (!this.shouldPrint(logLevel)) {
       return;
@@ -375,9 +486,9 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * When the data added in the log item when contains object references,
-   * JSON.stringify() doesn't try to solve them and throws an error: TypeError: cyclic object value.
-   * To mitigate this issue, this function will find and remove the cyclic references.
+   * When the data added in the log item contains object references,
+   * JSON.stringify() doesn't try to solve them and instead throws an error: TypeError: cyclic object value.
+   * To mitigate this issue, this method will find and remove all cyclic references.
    *
    * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Cyclic_object_value
    * @private
@@ -401,18 +512,49 @@ class Logger implements ClassThatLogs {
     };
   }
 
+  /**
+   * Sets the Logger's customer config service instance, which will be used
+   * to fetch environment variables.
+   *
+   * @private
+   * @param {ConfigServiceInterface} customConfigService
+   * @returns {void}
+   */
   private setCustomConfigService(customConfigService?: ConfigServiceInterface): void {
     this.customConfigService = customConfigService ? customConfigService : undefined;
   }
 
+  /**
+   * Sets the Logger's custom config service instance, which will be used
+   * to fetch environment variables.
+   *
+   * @private
+   * @param {ConfigServiceInterface} customConfigService
+   * @returns {void}
+   */
   private setEnvVarsService(): void {
     this.envVarsService = new EnvironmentVariablesService();
   }
 
+  /**
+   * It sets the log formatter instance, in charge of giving a custom format
+   * to the structured logs
+   *
+   * @private
+   * @param {LogFormatterInterface} logFormatter
+   * @returns {void}
+   */
   private setLogFormatter(logFormatter?: LogFormatterInterface): void {
     this.logFormatter = logFormatter || new PowertoolLogFormatter();
   }
 
+  /**
+   * It sets the Logger's instance log level.
+   *
+   * @private
+   * @param {LogLevel} logLevel
+   * @returns {void}
+   */
   private setLogLevel(logLevel?: LogLevel): void {
     if (this.isValidLogLevel(logLevel)) {
       this.logLevel = (<LogLevel>logLevel).toUpperCase();
@@ -435,12 +577,27 @@ class Logger implements ClassThatLogs {
     this.logLevel = Logger.defaultLogLevel;
   }
 
+  /**
+   * If the sample rate feature is enabled, it sets a propriety that tracks whether this Lambda function invocation
+   * will print logs or not.
+   *
+   * @private
+   * @returns {void}
+   */
   private setLogsSampled(): void {
     const sampleRateValue = this.getSampleRateValue();
     // TODO: revisit Math.random() as it's not a real randomization
     this.logsSampled = sampleRateValue !== undefined && (sampleRateValue === 1 || Math.random() < sampleRateValue);
   }
 
+  /**
+   * It configures the Logger instance settings that will affect the Logger's behaviour
+   * and the content of all logs.
+   *
+   * @private
+   * @param {LoggerOptions} options
+   * @returns {Logger}
+   */
   private setOptions(options: LoggerOptions): Logger {
     const {
       logLevel,
@@ -465,6 +622,15 @@ class Logger implements ClassThatLogs {
     return this;
   }
 
+  /**
+   * It adds important data to the Logger instance that will affect the content of all logs.
+   *
+   * @param {string} serviceName
+   * @param {Environment} environment
+   * @param {LogAttributes} persistentLogAttributes
+   * @private
+   * @returns {void}
+   */
   private setPowertoolLogData(
     serviceName?: string,
     environment?: Environment,
@@ -486,6 +652,15 @@ class Logger implements ClassThatLogs {
     );
   }
 
+  /**
+   * It checks whether the current log item should/can be printed.
+   *
+   * @param {string} serviceName
+   * @param {Environment} environment
+   * @param {LogAttributes} persistentLogAttributes
+   * @private
+   * @returns {boolean}
+   */
   private shouldPrint(logLevel: LogLevel): boolean {
     if (this.logLevelThresholds[logLevel] >= this.logLevelThresholds[this.getLogLevel()]) {
       return true;
diff --git a/packages/logger/src/config/ConfigService.ts b/packages/logger/src/config/ConfigService.ts
index 31663bc56c..4f38cf6ae6 100644
--- a/packages/logger/src/config/ConfigService.ts
+++ b/packages/logger/src/config/ConfigService.ts
@@ -1,21 +1,62 @@
 import { ConfigServiceInterface } from '.';
 
+/**
+ * Abstract class ConfigService
+ *
+ * This class defines common methods and variables that can be set by the developer
+ * in the runtime.
+ *
+ * @class
+ * @abstract
+ * @implements {ConfigServiceInterface}
+ * @see https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars.html#configuration-envvars-runtime
+ * @see https://awslabs.github.io/aws-lambda-powertools-typescript/latest/#environment-variables
+ */
 abstract class ConfigService implements ConfigServiceInterface {
 
-  // Custom environment variables
+  /**
+   * @see https://awslabs.github.io/aws-lambda-powertools-typescript/latest/#environment-variables
+   * @protected
+   */
   protected currentEnvironmentVariable = 'ENVIRONMENT';
   protected logLevelVariable = 'LOG_LEVEL';
   protected sampleRateValueVariable = 'POWERTOOLS_LOGGER_SAMPLE_RATE';
   protected serviceNameVariable = 'POWERTOOLS_SERVICE_NAME';
 
+  /**
+   * It returns the value of an environment variable that has given name.
+   *
+   * @param {string} name
+   * @returns {string}
+   */
   public abstract get(name: string): string;
 
+  /**
+   * It returns the value of the ENVIRONMENT environment variable.
+   *
+   * @returns {string}
+   */
   public abstract getCurrentEnvironment(): string;
 
+  /**
+   * It returns the value of the LOG_LEVEL environment variable.
+   *
+   * @returns {string}
+   */
   public abstract getLogLevel(): string;
 
+  /**
+   * It returns the value of the POWERTOOLS_LOGGER_SAMPLE_RATE environment variable.
+   *
+   * @returns {string|undefined}
+   */
   public abstract getSampleRateValue(): number | undefined;
 
+  /**
+   * It returns the value of the POWERTOOLS_SERVICE_NAME environment variable.
+   *
+   * @returns {string}
+   */
   public abstract getServiceName(): string;
 
 }
diff --git a/packages/logger/src/config/ConfigServiceInterface.ts b/packages/logger/src/config/ConfigServiceInterface.ts
index 3659acea66..0e9b62a409 100644
--- a/packages/logger/src/config/ConfigServiceInterface.ts
+++ b/packages/logger/src/config/ConfigServiceInterface.ts
@@ -1,13 +1,46 @@
+/**
+ * Interface ConfigServiceInterface
+ *
+ * @interface
+ * @see https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars.html#configuration-envvars-runtime
+ * @see https://awslabs.github.io/aws-lambda-powertools-typescript/latest/#environment-variables
+ */
 interface ConfigServiceInterface {
 
+  /**
+   * It returns the value of an environment variable that has given name.
+   *
+   * @param {string} name
+   * @returns {string}
+   */
   get(name: string): string
 
+  /**
+   * It returns the value of the ENVIRONMENT environment variable.
+   *
+   * @returns {string}
+   */
   getCurrentEnvironment(): string
 
+  /**
+   * It returns the value of the LOG_LEVEL environment variable.
+   *
+   * @returns {string}
+   */
   getLogLevel(): string
 
+  /**
+   * It returns the value of the POWERTOOLS_LOGGER_SAMPLE_RATE environment variable.
+   *
+   * @returns {string|undefined}
+   */
   getSampleRateValue(): number | undefined
 
+  /**
+   * It returns the value of the POWERTOOLS_SERVICE_NAME environment variable.
+   *
+   * @returns {string}
+   */
   getServiceName(): string
 
 }
diff --git a/packages/logger/src/config/EnvironmentVariablesService.ts b/packages/logger/src/config/EnvironmentVariablesService.ts
index 6553e93166..7c7c075bb7 100644
--- a/packages/logger/src/config/EnvironmentVariablesService.ts
+++ b/packages/logger/src/config/EnvironmentVariablesService.ts
@@ -1,5 +1,18 @@
 import { ConfigService } from '.';
 
+/**
+ * Class EnvironmentVariablesService
+ *
+ * This class is used to return environment variables that are available in the runtime of
+ * the current Lambda invocation.
+ * These variables can be a mix of runtime environment variables set by AWS and
+ * variables that can be set by the developer additionally.
+ *
+ * @class
+ * @extends {ConfigService}
+ * @see https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars.html#configuration-envvars-runtime
+ * @see https://awslabs.github.io/aws-lambda-powertools-typescript/latest/#environment-variables
+ */
 class EnvironmentVariablesService extends ConfigService {
 
   // Reserved environment variables
@@ -9,46 +22,97 @@ class EnvironmentVariablesService extends ConfigService {
   private memoryLimitInMBVariable = 'AWS_LAMBDA_FUNCTION_MEMORY_SIZE';
   private xRayTraceIdVariable = '_X_AMZN_TRACE_ID';
 
+  /**
+   * It returns a the value of an environment variable that has given name.
+   *
+   * @param {string} name
+   * @returns {string}
+   */
   public get(name: string): string {
     return process.env[name]?.trim() || '';
   }
 
+  /**
+   * It returns the value of the AWS_REGION environment variable.
+   *
+   * @returns {string}
+   */
   public getAwsRegion(): string {
     return this.get(this.awsRegionVariable);
   }
 
+  /**
+   * It returns the value of the ENVIRONMENT environment variable.
+   *
+   * @returns {string}
+   */
   public getCurrentEnvironment(): string {
     return this.get(this.currentEnvironmentVariable);
   }
 
+  /**
+   * It returns the value of the AWS_LAMBDA_FUNCTION_MEMORY_SIZE environment variable.
+   *
+   * @returns {string}
+   */
   public getFunctionMemory(): number {
     const value = this.get(this.memoryLimitInMBVariable);
 
     return Number(value);
   }
 
+  /**
+   * It returns the value of the AWS_LAMBDA_FUNCTION_NAME environment variable.
+   *
+   * @returns {string}
+   */
   public getFunctionName(): string {
     return this.get(this.functionNameVariable);
   }
 
+  /**
+   * It returns the value of the AWS_LAMBDA_FUNCTION_VERSION environment variable.
+   *
+   * @returns {string}
+   */
   public getFunctionVersion(): string {
     return this.get(this.functionVersionVariable);
   }
 
+  /**
+   * It returns the value of the LOG_LEVEL environment variable.
+   *
+   * @returns {string}
+   */
   public getLogLevel(): string {
     return this.get(this.logLevelVariable);
   }
 
+  /**
+   * It returns the value of the POWERTOOLS_LOGGER_SAMPLE_RATE environment variable.
+   *
+   * @returns {string|undefined}
+   */
   public getSampleRateValue(): number | undefined {
     const value = this.get(this.sampleRateValueVariable);
 
     return (value && value.length > 0) ? Number(value) : undefined;
   }
 
+  /**
+   * It returns the value of the POWERTOOLS_SERVICE_NAME environment variable.
+   *
+   * @returns {string}
+   */
   public getServiceName(): string {
     return this.get(this.serviceNameVariable);
   }
 
+  /**
+   * It returns the value of the _X_AMZN_TRACE_ID environment variable.
+   *
+   * @returns {string}
+   */
   public getXrayTraceId(): string {
     return this.get(this.xRayTraceIdVariable);
   }
diff --git a/packages/logger/src/formatter/LogFormatter.ts b/packages/logger/src/formatter/LogFormatter.ts
index 594e50cb7d..05fbb1300d 100644
--- a/packages/logger/src/formatter/LogFormatter.ts
+++ b/packages/logger/src/formatter/LogFormatter.ts
@@ -1,10 +1,31 @@
 import { LogFormatterInterface } from '.';
 import { LogAttributes, UnformattedAttributes } from '../types';
 
+/**
+ * Abstract class LogFormatter
+ *
+ * This class defines and implements common methods for the formatting of log attributes.
+ *
+ * @class
+ * @abstract
+ * @implements {LogFormatterInterface}
+ */
 abstract class LogFormatter implements LogFormatterInterface {
 
+  /**
+   * It formats key-value pairs of log attributes.
+   *
+   * @param {UnformattedAttributes} attributes
+   * @returns {LogAttributes}
+   */
   public abstract formatAttributes(attributes: UnformattedAttributes): LogAttributes;
 
+  /**
+   * It formats a given Error parameter.
+   *
+   * @param {Error} error
+   * @returns {LogAttributes}
+   */
   public formatError(error: Error): LogAttributes {
     return {
       name: error.name,
@@ -14,10 +35,22 @@ abstract class LogFormatter implements LogFormatterInterface {
     };
   }
 
+  /**
+   * It formats a date into a string in simplified extended ISO format (ISO 8601).
+   *
+   * @param {Date} now
+   * @returns {string}
+   */
   public formatTimestamp(now: Date): string {
     return now.toISOString();
   }
 
+  /**
+   * It returns a string containing the location of an error, given a particular stack trace.
+   *
+   * @param stack
+   * @returns {string}
+   */
   public getCodeLocation(stack?: string): string {
     if (!stack) {
       return '';
diff --git a/packages/logger/src/formatter/LogFormatterInterface.ts b/packages/logger/src/formatter/LogFormatterInterface.ts
index 04e3b69e3f..2be8173c10 100644
--- a/packages/logger/src/formatter/LogFormatterInterface.ts
+++ b/packages/logger/src/formatter/LogFormatterInterface.ts
@@ -1,9 +1,26 @@
 import { LogAttributes, UnformattedAttributes } from '../types';
 
+/**
+ * Interface LogFormatterInterface
+ *
+ * @interface
+ */
 interface LogFormatterInterface {
 
+  /**
+   * It formats key-value pairs of log attributes.
+   *
+   * @param {UnformattedAttributes} attributes
+   * @returns {PowertoolLog}
+   */
   formatAttributes(attributes: UnformattedAttributes): LogAttributes
 
+  /**
+   * It formats a given Error parameter.
+   *
+   * @param {Error} error
+   * @returns {LogAttributes}
+   */
   formatError(error: Error): LogAttributes
 
 }
diff --git a/packages/logger/src/formatter/PowertoolLogFormatter.ts b/packages/logger/src/formatter/PowertoolLogFormatter.ts
index f29e1b5dd8..c4bd7bc34b 100644
--- a/packages/logger/src/formatter/PowertoolLogFormatter.ts
+++ b/packages/logger/src/formatter/PowertoolLogFormatter.ts
@@ -2,8 +2,21 @@ import { LogFormatter } from '.';
 import { UnformattedAttributes } from '../types';
 import { PowertoolLog } from '../types/formats';
 
+/**
+ * This class is used to transform a set of log key-value pairs
+ * in the AWS Lambda Powertools' default structure log format.
+ *
+ * @class
+ * @extends {LogFormatter}
+ */
 class PowertoolLogFormatter extends LogFormatter {
 
+  /**
+   * It formats key-value pairs of log attributes.
+   *
+   * @param {UnformattedAttributes} attributes
+   * @returns {PowertoolLog}
+   */
   public formatAttributes(attributes: UnformattedAttributes): PowertoolLog {
     return {
       cold_start: attributes.lambdaContext?.coldStart,
diff --git a/packages/logger/src/middleware/middy.ts b/packages/logger/src/middleware/middy.ts
index e06b19e156..cc5b2e54bb 100644
--- a/packages/logger/src/middleware/middy.ts
+++ b/packages/logger/src/middleware/middy.ts
@@ -1,6 +1,13 @@
 import type { Logger } from '../Logger';
 import middy from '@middy/core';
 
+/**
+ * Middy middleware that adds the current Lambda invocation's context
+ * inside all log items.
+ *
+ * @param {Logger|Logger[]} target
+ * @returns middy.MiddlewareObj
+ */
 const injectLambdaContext = (target: Logger | Logger[]): middy.MiddlewareObj => {
   const injectLambdaContextBefore = async (request: middy.Request): Promise<void> => {
     const loggers = target instanceof Array ? target : [target];

From acc172a243fd2bed0516e1e6ae3fe3cc077ec200 Mon Sep 17 00:00:00 2001
From: Sara Gerion <sgerion@amazon.com>
Date: Wed, 19 Jan 2022 22:08:03 +0100
Subject: [PATCH 03/12] fix(logger): jsdocs finetuning

---
 packages/logger/src/Logger.ts | 29 +++++++++++------------------
 1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
index 4ac0faa269..e004e59f25 100644
--- a/packages/logger/src/Logger.ts
+++ b/packages/logger/src/Logger.ts
@@ -44,10 +44,6 @@ import type {
  */
 class Logger implements ClassThatLogs {
 
-  /**
-   *
-   * @private
-   */
   private static coldStart?: boolean = undefined;
 
   private static coldStartEvaluated: boolean = false;
@@ -87,7 +83,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * Adds the current AWS Lambda's invocation context data to the powertoolLogData propriety of the instance.
+   * It adds the current Lambda function's invocation context data to the powertoolLogData propriety of the instance.
    * This context data will be part of all printed log items.
    *
    * @param {Context} context
@@ -110,7 +106,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * Adds given attributes (key-value pairs) to all log items generated by this Logger instance.
+   * it adds the given attributes (key-value pairs) to all log items generated by this Logger instance.
    *
    * @param {LogAttributes} attributes
    * @returns {void}
@@ -130,7 +126,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * Creates a separate Logger instance, identical to the current one.
+   * it creates a separate Logger instance, identical to the current one.
    * It's possible to overwrite the new instance options by passing them.
    *
    * @param {LoggerOptions} options
@@ -175,8 +171,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * It returns a boolean true value if the current Lambda function invocation has been already evaluated to
-   * determine if it's a cold start, false if not.
+   * It returns a boolean value which is true if the current Lambda function cold start has been already evaluated, false if not.
    *
    * @static
    * @returns {boolean}
@@ -186,7 +181,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * It returns a boolean true value if the current Lambda function invocation has a cold start, false otherwise.
+   * It returns an optional boolean value, true if the current Lambda function invocation has a cold start, false otherwise.
    *
    * @static
    * @returns {boolean | undefined}
@@ -196,8 +191,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * It returns a boolean true value if, in case of sample rating feature enabled, the current
-   * Lambda function invocation's logs will be printed to stdout. It returns false otherwise.
+   * It returns a boolean value, if true all the logs will be printed.
    *
    * @returns {boolean}
    */
@@ -250,7 +244,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * Sets the value of a flag static propriety that tracks whether
+   * It sets the value of a flag static propriety that tracks whether
    * the cold start evaluation already took place.
    *
    * @param {boolean} value
@@ -262,11 +256,11 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * Sets the value of a flag static propriety that tracks whether
+   * It sets the value of a flag static propriety that tracks whether
    * the current Lambda invocation experienced a cold start.
    *
-   * @param {boolean | undefined} value
    * @static
+   * @param {boolean | undefined} value
    * @returns {void}
    */
   public static setColdStartValue(value: boolean | undefined): void {
@@ -276,7 +270,7 @@ class Logger implements ClassThatLogs {
   /**
    * It sets the user-provided sample rate value.
    *
-   * @param {number} sampleRateValue
+   * @param {number} [sampleRateValue]
    * @returns {void}
    */
   public setSampleRateValue(sampleRateValue?: number): void {
@@ -298,8 +292,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * Adds information to a class propriety that contains information that
-   * is printed in all log items.
+   * It stored information that is printed in all log items.
    *
    * @param {Partial<PowertoolLogData>} attributesArray
    * @private

From 85ef8e68724e58a1707a10fcd68a18d46bde7535 Mon Sep 17 00:00:00 2001
From: Sara Gerion <sgerion@amazon.com>
Date: Wed, 19 Jan 2022 23:01:18 +0100
Subject: [PATCH 04/12] fix(logger): removed trailing eslint jsdocs flag

---
 .eslintrc.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.eslintrc.js b/.eslintrc.js
index a8cbf8ceef..b83ce24ffc 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -7,7 +7,7 @@ module.exports = {
   },
   extends: [ 'plugin:@typescript-eslint/eslint-recommended', 'plugin:@typescript-eslint/recommended' ],
   parser: '@typescript-eslint/parser',
-  plugins: ['@typescript-eslint', 'jsdoc'],
+  plugins: ['@typescript-eslint'],
   settings: {
     'import/resolver': {
       node: {},

From 4e3a532966f9c77bb4d260c8e042becd5eeff05e Mon Sep 17 00:00:00 2001
From: Sara Gerion <47529391+saragerion@users.noreply.github.com>
Date: Thu, 20 Jan 2022 09:26:10 +0100
Subject: [PATCH 05/12] Update
 packages/logger/src/config/EnvironmentVariablesService.ts

Co-authored-by: Florian Chazal <florianchazal@gmail.com>
---
 packages/logger/src/config/EnvironmentVariablesService.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/logger/src/config/EnvironmentVariablesService.ts b/packages/logger/src/config/EnvironmentVariablesService.ts
index 7c7c075bb7..588af64a01 100644
--- a/packages/logger/src/config/EnvironmentVariablesService.ts
+++ b/packages/logger/src/config/EnvironmentVariablesService.ts
@@ -23,7 +23,7 @@ class EnvironmentVariablesService extends ConfigService {
   private xRayTraceIdVariable = '_X_AMZN_TRACE_ID';
 
   /**
-   * It returns a the value of an environment variable that has given name.
+   * It returns the value of an environment variable that has given name.
    *
    * @param {string} name
    * @returns {string}

From 10e07d7a86b6dd6df5050d80b88a8132ec325259 Mon Sep 17 00:00:00 2001
From: Sara Gerion <47529391+saragerion@users.noreply.github.com>
Date: Thu, 20 Jan 2022 10:25:20 +0100
Subject: [PATCH 06/12] Update packages/logger/src/Logger.ts

Co-authored-by: Andrea Amorosi <dreamorosi@gmail.com>
---
 packages/logger/src/Logger.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
index e004e59f25..f10590989d 100644
--- a/packages/logger/src/Logger.ts
+++ b/packages/logger/src/Logger.ts
@@ -83,7 +83,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * It adds the current Lambda function's invocation context data to the powertoolLogData propriety of the instance.
+   * It adds the current Lambda function's invocation context data to the powertoolLogData property of the instance.
    * This context data will be part of all printed log items.
    *
    * @param {Context} context

From 9e3452dfd0e9081eb9cc274afc97736c30562fbf Mon Sep 17 00:00:00 2001
From: Sara Gerion <47529391+saragerion@users.noreply.github.com>
Date: Thu, 20 Jan 2022 10:25:47 +0100
Subject: [PATCH 07/12] Update packages/logger/src/Logger.ts

Co-authored-by: Andrea Amorosi <dreamorosi@gmail.com>
---
 packages/logger/src/Logger.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
index f10590989d..ef5a1ba8e3 100644
--- a/packages/logger/src/Logger.ts
+++ b/packages/logger/src/Logger.ts
@@ -106,7 +106,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * it adds the given attributes (key-value pairs) to all log items generated by this Logger instance.
+   * It adds the given attributes (key-value pairs) to all log items generated by this Logger instance.
    *
    * @param {LogAttributes} attributes
    * @returns {void}

From c95159f9aaa2b14c64634927fdf37ea4e2cd81a9 Mon Sep 17 00:00:00 2001
From: Sara Gerion <47529391+saragerion@users.noreply.github.com>
Date: Thu, 20 Jan 2022 10:25:53 +0100
Subject: [PATCH 08/12] Update packages/logger/src/Logger.ts

Co-authored-by: Andrea Amorosi <dreamorosi@gmail.com>
---
 packages/logger/src/Logger.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
index ef5a1ba8e3..4b79686a4c 100644
--- a/packages/logger/src/Logger.ts
+++ b/packages/logger/src/Logger.ts
@@ -126,7 +126,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * it creates a separate Logger instance, identical to the current one.
+   * It creates a separate Logger instance, identical to the current one
    * It's possible to overwrite the new instance options by passing them.
    *
    * @param {LoggerOptions} options

From 81096ca4c157e5ab0fd449ed50930bc03d544c16 Mon Sep 17 00:00:00 2001
From: Sara Gerion <47529391+saragerion@users.noreply.github.com>
Date: Thu, 20 Jan 2022 10:26:02 +0100
Subject: [PATCH 09/12] Update packages/logger/src/Logger.ts

Co-authored-by: Andrea Amorosi <dreamorosi@gmail.com>
---
 packages/logger/src/Logger.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
index 4b79686a4c..f4f54af332 100644
--- a/packages/logger/src/Logger.ts
+++ b/packages/logger/src/Logger.ts
@@ -171,7 +171,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * It returns a boolean value which is true if the current Lambda function cold start has been already evaluated, false if not.
+   * It returns a boolean value which is true if the current Lambda function cold start has been already evaluated, false otherwise.
    *
    * @static
    * @returns {boolean}

From 61e105313bd1e8f9a585ef31087bd0398af36d9f Mon Sep 17 00:00:00 2001
From: Sara Gerion <47529391+saragerion@users.noreply.github.com>
Date: Thu, 20 Jan 2022 10:26:21 +0100
Subject: [PATCH 10/12] Update packages/logger/src/Logger.ts

Co-authored-by: Andrea Amorosi <dreamorosi@gmail.com>
---
 packages/logger/src/Logger.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
index f4f54af332..918e6971b9 100644
--- a/packages/logger/src/Logger.ts
+++ b/packages/logger/src/Logger.ts
@@ -292,7 +292,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * It stored information that is printed in all log items.
+   * It stores information that is printed in all log items.
    *
    * @param {Partial<PowertoolLogData>} attributesArray
    * @private

From 637759b59a5c01dc7263714d1dcd691afd4574da Mon Sep 17 00:00:00 2001
From: Sara Gerion <47529391+saragerion@users.noreply.github.com>
Date: Thu, 20 Jan 2022 10:26:26 +0100
Subject: [PATCH 11/12] Update packages/logger/src/Logger.ts

Co-authored-by: Andrea Amorosi <dreamorosi@gmail.com>
---
 packages/logger/src/Logger.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
index 918e6971b9..f2f12670cf 100644
--- a/packages/logger/src/Logger.ts
+++ b/packages/logger/src/Logger.ts
@@ -571,7 +571,7 @@ class Logger implements ClassThatLogs {
   }
 
   /**
-   * If the sample rate feature is enabled, it sets a propriety that tracks whether this Lambda function invocation
+   * If the sample rate feature is enabled, it sets a property that tracks whether this Lambda function invocation
    * will print logs or not.
    *
    * @private

From 1472f7167988af7b998b2bba6d50bc3c32ab930f Mon Sep 17 00:00:00 2001
From: Sara Gerion <sgerion@amazon.com>
Date: Thu, 20 Jan 2022 11:28:53 +0100
Subject: [PATCH 12/12] docs(logger): improve example for jsdocs

---
 .../example-function.MyFunctionWithMiddy.ts   |  2 +-
 packages/logger/src/Logger.ts                 | 80 ++++++++++++++++---
 packages/logger/src/formatter/LogFormatter.ts |  2 -
 .../src/formatter/LogFormatterInterface.ts    |  2 -
 packages/logger/src/middleware/middy.ts       | 26 +++++-
 packages/tracing/src/Tracer.ts                |  2 +-
 packages/tracing/tests/unit/middy.test.ts     |  2 +-
 7 files changed, 96 insertions(+), 20 deletions(-)

diff --git a/examples/cdk/src/example-function.MyFunctionWithMiddy.ts b/examples/cdk/src/example-function.MyFunctionWithMiddy.ts
index c2e6f8d444..6b743512aa 100644
--- a/examples/cdk/src/example-function.MyFunctionWithMiddy.ts
+++ b/examples/cdk/src/example-function.MyFunctionWithMiddy.ts
@@ -62,7 +62,7 @@ const lambdaHandler = async (event: typeof Events.Custom.CustomEvent, context: C
   return res;
 };
 
-// We instrument the handler with the various Middy middlewares
+// We instrument the handler with the various Middy middleware
 export const handler = middy(lambdaHandler)
   .use(captureLambdaHandler(tracer))
   .use(
diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
index 3353b8fb17..cd846a010c 100644
--- a/packages/logger/src/Logger.ts
+++ b/packages/logger/src/Logger.ts
@@ -19,25 +19,87 @@ import type {
 } from './types';
 
 /**
- *
- * # Logger class
- *
  * ## Intro
- *
  * The Logger utility provides an opinionated logger with output structured as JSON.
  *
  * ## Key features
+ *  * Capture key fields from Lambda context, cold start and structures logging output as JSON
+ *  * Log Lambda context when instructed (disabled by default)
+ *  * Log sampling prints all logs for a percentage of invocations (disabled by default)
+ *  * Append additional keys to structured log at any point in time
+ *
+ * ## Usage
+ *
+ * For more usage examples, see [our documentation](https://awslabs.github.io/aws-lambda-powertools-typescript/latest/core/logger/).
+ *
+ * ### Basic usage
+ *
+ * @example
+ * ```typescript
+ * import { Logger } from "@aws-lambda-powertools/logger";
+ *
+ * // Logger parameters fetched from the environment variables:
+ * const logger = new Logger();
+ * ```
  *
- * - Capture key fields from Lambda context, cold start and structures logging output as JSON
- * - Log Lambda context when instructed (disabled by default)
- * - Log sampling prints all logs for a percentage of invocations (disabled by default)
- * - Append additional keys to structured log at any point in time
+ * ### Functions usage with manual instrumentation
  *
- * ## Basic usage
+ * If you prefer to manually instrument your Lambda handler you can use the methods in the Logger class directly.
  *
+ * @example
+ * ```typescript
  * import { Logger } from "@aws-lambda-powertools/logger";
+ *
  * const logger = new Logger();
  *
+ * export const handler = async (_event, context) => {
+ *     logger.addContext(context);
+ *     logger.info("This is an INFO log with some context");
+ * };
+ * ```
+ *
+ * ### Functions usage with middleware
+ *
+ * If you use function-based Lambda handlers you can use the [injectLambdaContext()](#injectLambdaContext)
+ * middy middleware to automatically add context to your Lambda logs.
+ *
+ * @example
+ * ```typescript
+ * import { Logger, injectLambdaContext } from "@aws-lambda-powertools/logger";
+ * import middy from '@middy/core';
+ *
+ * const logger = new Logger();
+ *
+ * const lambdaHandler = async (_event: any, _context: any) => {
+ *     logger.info("This is an INFO log with some context");
+ * };
+ *
+ * export const handler = middy(lambdaHandler).use(injectLambdaContext(logger));
+ * ```
+ *
+ * ### Object oriented usage with decorators
+ *
+ * If instead you use TypeScript classes to wrap your Lambda handler you can use the [@logger.injectLambdaContext()](./_aws_lambda_powertools_logger.Logger.html#injectLambdaContext) decorator.
+ *
+ * @example
+ * ```typescript
+ * import { Logger } from "@aws-lambda-powertools/logger";
+ * import { LambdaInterface } from '@aws-lambda-powertools/commons';
+ *
+ * const logger = new Logger();
+ *
+ * class Lambda implements LambdaInterface {
+ *     // Decorate your handler class method
+ *     @logger.injectLambdaContext()
+ *     public async handler(_event: any, _context: any): Promise<void> {
+ *         logger.info("This is an INFO log with some context");
+ *     }
+ * }
+ *
+ * export const myFunction = new Lambda();
+ * export const handler = myFunction.handler;
+ * ```
+ *
  * @class
  * @implements {ClassThatLogs}
  * @see https://awslabs.github.io/aws-lambda-powertools-typescript/latest/core/logger/
diff --git a/packages/logger/src/formatter/LogFormatter.ts b/packages/logger/src/formatter/LogFormatter.ts
index 05fbb1300d..29b47f99fd 100644
--- a/packages/logger/src/formatter/LogFormatter.ts
+++ b/packages/logger/src/formatter/LogFormatter.ts
@@ -2,8 +2,6 @@ import { LogFormatterInterface } from '.';
 import { LogAttributes, UnformattedAttributes } from '../types';
 
 /**
- * Abstract class LogFormatter
- *
  * This class defines and implements common methods for the formatting of log attributes.
  *
  * @class
diff --git a/packages/logger/src/formatter/LogFormatterInterface.ts b/packages/logger/src/formatter/LogFormatterInterface.ts
index 2be8173c10..1139443c28 100644
--- a/packages/logger/src/formatter/LogFormatterInterface.ts
+++ b/packages/logger/src/formatter/LogFormatterInterface.ts
@@ -1,8 +1,6 @@
 import { LogAttributes, UnformattedAttributes } from '../types';
 
 /**
- * Interface LogFormatterInterface
- *
  * @interface
  */
 interface LogFormatterInterface {
diff --git a/packages/logger/src/middleware/middy.ts b/packages/logger/src/middleware/middy.ts
index cc5b2e54bb..d0353962a3 100644
--- a/packages/logger/src/middleware/middy.ts
+++ b/packages/logger/src/middleware/middy.ts
@@ -2,11 +2,29 @@ import type { Logger } from '../Logger';
 import middy from '@middy/core';
 
 /**
- * Middy middleware that adds the current Lambda invocation's context
- * inside all log items.
+ * A middy middleware that adds the current Lambda invocation's context inside all log items.
  *
- * @param {Logger|Logger[]} target
- * @returns middy.MiddlewareObj
+ * ## Usage
+ *
+ * @example
+ * ```typescript
+ * import { Logger, injectLambdaContext } from "@aws-lambda-powertools/logger";
+ *
+ * import middy from '@middy/core';
+ *
+ *
+ * const logger = new Logger();
+ *
+ * const lambdaHandler = async (_event: any, _context: any) => {
+ *     logger.info("This is an INFO log with some context");
+ * };
+ *
+ *
+ * export const handler = middy(lambdaHandler).use(injectLambdaContext(logger));
+ * ```
+ *
+ * @param {Logger|Logger[]} target - The Tracer instance to use for tracing
+ * @returns {middy.MiddlewareObj} - The middy middleware object
  */
 const injectLambdaContext = (target: Logger | Logger[]): middy.MiddlewareObj => {
   const injectLambdaContextBefore = async (request: middy.Request): Promise<void> => {
diff --git a/packages/tracing/src/Tracer.ts b/packages/tracing/src/Tracer.ts
index 12e9669aed..8ac49de38e 100644
--- a/packages/tracing/src/Tracer.ts
+++ b/packages/tracing/src/Tracer.ts
@@ -21,7 +21,7 @@ import { Segment, Subsegment } from 'aws-xray-sdk-core';
  * 
  * For more usage examples, see [our documentation](https://awslabs.github.io/aws-lambda-powertools-typescript/latest/core/tracer/).
  * 
- * ### Functions usage with middlewares
+ * ### Functions usage with middleware
  * 
  * If you use function-based Lambda handlers you can use the [captureLambdaHandler()](./_aws_lambda_powertools_tracer.Tracer.html) middy middleware to automatically:
  * * handle the subsegment lifecycle 
diff --git a/packages/tracing/tests/unit/middy.test.ts b/packages/tracing/tests/unit/middy.test.ts
index 0bf588c522..5829ba25cd 100644
--- a/packages/tracing/tests/unit/middy.test.ts
+++ b/packages/tracing/tests/unit/middy.test.ts
@@ -14,7 +14,7 @@ jest.spyOn(console, 'debug').mockImplementation(() => null);
 jest.spyOn(console, 'warn').mockImplementation(() => null);
 jest.spyOn(console, 'error').mockImplementation(() => null);
 
-describe('Middy middlewares', () => {
+describe('Middy middleware', () => {
   const ENVIRONMENT_VARIABLES = process.env;
   const context = {
     callbackWaitsForEmptyEventLoop: true,