Added Node API

README.md

@@ -162,6 +162,18 @@ _Default: `tsconfig.json`_
 Path to a TypeScript configuration file to read TypeScript compiler options from.
 This will help inform the generated ESLint configuration file's [env](https://eslint.org/docs/user-guide/configuring#specifying-parser-options) settings.
 
+
+## Node API
+
+You can use `tslint-to-eslint-config` programmatically via its exported functions.
+See [docs/API](./docs/API.md) for details.
+
+```ts
+import { convertLintConfig } from "tslint-to-eslint-config";
+
+const result = await convertLintConfig();
+```
+
 ## Development
 
 See the [Code of Conduct](./.github/CODE_OF_CONDUCT.md) and [general development docs](./docs/Development.md). 💖

docs/API.md

@@ -0,0 +1,65 @@
+# API
+
+You can use `tslint-to-eslint-config` programmatically in your Node apps.
+It provides a **[`convertTSLintConfig`](#convertTSLintConfig)** function to find relevant configurations on disk and output the generated ESLint configuration.
+
+## `convertTSLintConfig`
+
+```ts
+import { convertTSLintConfig } from "tslint-to-eslint-config";
+
+const result = await convertTSLintConfig();
+```
+
+Finds relevant configurations on disk and outputs the generated ESLint configuration.
+
+Optionally takes in the same settings you can provide via the CLI:
+
+* `config`: Output ESLint configuration file path _(default: `.eslintrc.js`)_.
+* `eslint`: Original ESLint configuration file path _(default: `.eslintrc.js`)_.
+* `package`: Original packages configuration file path _(default: `package.json`)_.
+* `prettier`: Whether to add `eslint-config-prettier` to the plugins list.
+* `tslint`: Original TSLint configuration file path _(default: `tslint.json`)_.
+* `typescript`: Original TypeScript configuration file path _(default: `tsconfig.json`)_.
+
+```ts
+import { convertTSLintConfig } from "tslint-to-eslint-config";
+
+const result = await convertTSLintConfig({
+    config: "./path/to/output/eslintrc.js",
+    eslint: "./path/to/input/eslintrc.js",
+    package: "./path/to/package.json", 
+    prettier: true, // Prettier: highly recommended!
+    tslint: "./path/to/tslint.json", 
+    typescript: "./path/to/tsconfig.json", 
+});
+```
+
+If the TSLint configuration or any manually specified configurations fail to read from disk, the result will contain:
+
+* `complaints`: String complaints describing the errors.
+* `status`: `ResultStatus.ConfigurationError` (`2`).
+
+If no error is detected, the result will contain:
+
+* `data`: Resultant ESLint configuration as:
+    * `formatted`: Stringified result per the output config path's file type.
+    * `raw`: Plain old JavaScript object.
+* `status`: `ResultStatus.Succeeded` (`0`).
+
+```ts
+import { convertTSLintConfig, ResultStatus } from "tslint-to-eslint-config";
+
+const result = await convertTSLintConfig({ /* ... */ });
+
+if (result.status !== ResultStatus.Succeeded) {
+    console.info("Oh no!");
+    console.error(result.complaints.join("\n"));
+} else {
+    console.info("Hooray!");
+    console.log(result.data.formatted);
+    console.log(result.data.raw);
+}
+```
+
+> See the provided `.d.ts` TypeScript typings for full descriptions of inputs and outputs.

docs/Architecture/Linters.md

@@ -3,10 +3,13 @@
 TSLint-to-ESLint linter configuration conversion is the first root-level converter run.
 Within `src/converters/lintConfigs/convertLintConfig.ts`, the following steps occur:
 
-1. Raw TSLint rules are mapped to their ESLint equivalents.
-2. Those ESLint equivalents are deduplicated and relevant preset(s) detected.
-3. Those deduplicated rules and metadata are written to the output configuration file.
-4. A summary of conversion results is printed, along with any now-missing packages.
+1. Deduplicated ESLint rules and metadata are generated from raw TSLint rules.
+    1a. Raw TSLint rules are mapped to their ESLint equivalents.
+    1b. Those ESLint equivalents are deduplicated and relevant preset(s) detected.
+2. Those deduplicated rules and metadata are written to the output configuration file.
+3. A summary of conversion results is printed, along with any now-missing packages.
+
+> Stepss 1 and 2 are the logic exported by the [Node API](../API.md) as [`convertTSLintConfig`](../API.md#convertTSLintConfig).
 
 ## Rule Conversion
 

docs/Dependencies.md

@@ -8,7 +8,7 @@ Its dependencies object is manually created in `src/cli/main.ts` and bound to th
 ## When to Use Dependencies
 
 Most functions don't need a `dependencies` object.
-Only add one if something should be stubbed out during tests.
+Only add one if something should be stubbed out during tests _or_ should be available to multiple callers.
 
 ## How to Use Dependencies
 

jest.config.js

@@ -4,6 +4,7 @@ module.exports = {
         "!./src/**/*.d.ts",
         "!./src/**/*.stubs.ts",
         "!./src/adapters/*.ts",
+        "!./src/api/*.ts",
         "!./src/cli/main.ts",
         "!./src/converters/editorConfigs/editorSettingsConverters.ts",
         "!./src/converters/lintConfigs/rules/ruleConverters.ts",

package.json

@@ -58,6 +58,7 @@
             "prettier --write"
         ]
     },
+    "main": "./src/index.js",
     "name": "tslint-to-eslint-config",
     "repository": {
         "type": "git",

src/api/convertTSLintConfigStandalone.ts

@@ -0,0 +1,73 @@
+import { createESLintConfiguration } from "../converters/lintConfigs/createESLintConfiguration";
+import { formatOutput } from "../converters/lintConfigs/formatting/formatOutput";
+import {
+    joinConfigConversionResults,
+    JoinedConversionResult,
+} from "../converters/lintConfigs/joinConfigConversionResults";
+import { findOriginalConfigurations } from "../input/findOriginalConfigurations";
+import {
+    ConfigurationErrorResult,
+    LintConfigConversionSettings,
+    ResultStatus,
+    SucceededDataResult,
+} from "../types";
+import {
+    createESLintConfigurationDependencies,
+    findOriginalConfigurationsDependencies,
+} from "./dependencies";
+
+/**
+ * Resultant configuration data from converting a TSLint configuration.
+ */
+export type TSLintConversionData = {
+    /**
+     * Formatted configuration string per the output file's extension.
+     */
+    formatted: string;
+
+    /**
+     * Object description of the resultant configuration data.
+     */
+    raw: JoinedConversionResult;
+};
+
+/**
+ * Finds relevant configurations on disk and outputs the generated ESLint configuration.
+ *
+ * @param settings - Settings to find and convert configurations to an ESLint configuration.
+ */
+export const convertTSLintConfigStandalone = async (
+    rawSettings: Partial<LintConfigConversionSettings> = {},
+): Promise<ConfigurationErrorResult | SucceededDataResult<TSLintConversionData>> => {
+    const settings = {
+        ...rawSettings,
+        config: ".eslintrc.js",
+    };
+    const originalConfigurations = await findOriginalConfigurations(
+        findOriginalConfigurationsDependencies,
+        settings,
+    );
+    if (originalConfigurations.status !== ResultStatus.Succeeded) {
+        return originalConfigurations;
+    }
+
+    const summarizedConfiguration = await createESLintConfiguration(
+        createESLintConfigurationDependencies,
+        originalConfigurations.data,
+        settings.prettier,
+        new Map(),
+    );
+
+    const output = joinConfigConversionResults(
+        summarizedConfiguration,
+        originalConfigurations.data,
+    );
+
+    return {
+        data: {
+            formatted: formatOutput(settings.config, output),
+            raw: output,
+        },
+        status: ResultStatus.Succeeded,
+    };
+};