fix: simpler TypeScript advice (cypress-io#195)

* fix: and pass extension from package nyc object if provided

Author: bahmutov

.circleci/config.yml

@@ -219,7 +219,8 @@ workflows:
                 name: Check code coverage 📈
                 command: |
                   ../../node_modules/.bin/check-coverage main.ts
-                  ../../node_modules/.bin/only-covered main.ts
+                  ../../node_modules/.bin/check-coverage calc.ts
+                  ../../node_modules/.bin/only-covered main.ts calc.ts
                 working_directory: examples/ts-example
 
       - cypress/run:

.github/ISSUE_TEMPLATE/bug_report.md

@@ -6,6 +6,9 @@ labels: ''
 assignees: ''
 ---
 
+**Logs and screenshots**
+Please provide debug logs by running Cypress from the terminal with `DEBUG=code-coverage` environment variable set, see the [Debugging](https://github.com/cypress-io/code-coverage#debugging) section of the README file.
+
 **Versions**
 
 - What is this plugin's version?
@@ -21,8 +24,5 @@ assignees: ''
 **Describe the bug**
 A clear and concise description of what the bug is.
 
-**Logs and screenshots**
-If possible, add the log from the terminal. You can turn on debugging logging, see [Debugging](https://github.com/cypress-io/code-coverage#debugging) section of the README file.
-
 **Link to the repo**
 Bugs with a reproducible example, like an open source repo showing the bug, are the most likely to be resolved.

README.md

@@ -229,26 +229,9 @@ Sometimes NYC tool might be installed in a different folder not in the current o
 
 ## TypeScript users
 
-TypeScript source files are NOT included in the code coverage report by default, even if they are properly instrumented. In order to tell `nyc` to include TS files in the report, you need to:
+TypeScript source files should be automatically included in the report, if they are instrumented.
 
-1. Add these dev dependencies that let Istanbul work with TypeScript
-
-```shell
-npm i -D @istanbuljs/nyc-config-typescript source-map-support
-```
-
-2. In `package.json` use the following `nyc` configuration object
-
-```json
-{
-  "nyc": {
-    "extends": "@istanbuljs/nyc-config-typescript",
-    "all": true
-  }
-}
-```
-
-See [examples/ts-example](examples/ts-example)
+See [examples/ts-example](examples/ts-example) and [bahmutov/cra-ts-code-coverage-example](https://github.com/bahmutov/cra-ts-code-coverage-example).
 
 ## Exclude code
 
@@ -413,6 +396,8 @@ npx nyc report --check-coverage true --lines 100 --include cypress/about.js
 npx nyc report --check-coverage true --lines 100 --include cypress/unit.js
 ```
 
+**Tip:** use [check-code-coverage](https://github.com/bahmutov/check-code-coverage) for stricter code coverage checks than `nyc report --check-coverage` allows.
+
 ### Markdown
 
 You can validate links in Markdown files in this directory by executing (Linux + Mac only) script

examples/ts-example/calc.ts

@@ -0,0 +1,3 @@
+export const add = (a: number, b: number) => {
+  return a + b
+}

examples/ts-example/main.ts

@@ -1,6 +1,4 @@
-const add = (a: number, b: number) => {
-  return a + b
-}
+import { add } from './calc'
 
 const sub = (a: number, b: number) => {
   return a - b

examples/ts-example/package.json

@@ -4,10 +4,6 @@
   "devDependencies": {
     "@babel/core": "7.9.0"
   },
-  "nyc": {
-    "extends": "@istanbuljs/nyc-config-typescript",
-    "all": true
-  },
   "scripts": {
     "start": "../../node_modules/.bin/parcel serve index.html",
     "build": "../../node_modules/.bin/parcel build index.html",

package.json

@@ -54,7 +54,6 @@
   },
   "devDependencies": {
     "@babel/core": "7.9.0",
-    "@istanbuljs/nyc-config-typescript": "1.0.1",
     "babel-plugin-istanbul": "6.0.0",
     "check-code-coverage": "1.0.1",
     "cypress": "4.3.0",
@@ -65,7 +64,6 @@
     "prettier": "1.19.1",
     "semantic-release": "17.0.4",
     "serve": "11.3.0",
-    "source-map-support": "0.5.16",
     "start-server-and-test": "1.10.11",
     "typescript": "3.8.3"
   }

task.js

@@ -148,6 +148,7 @@ const tasks = {
     // I am mostly worried about additional NYC options that are stored in
     // package.json and .nycrc resource files.
     // for now let's just camel case all options
+    // https://github.com/istanbuljs/nyc#common-configuration-options
     const nycReportOptions = {
       reportDir,
       tempDir: coverageFolder,
@@ -156,7 +157,14 @@ const tasks = {
       exclude: nycOptions.exclude,
       // from working with TypeScript code seems we need these settings too
       excludeAfterRemap: true,
-      extension: ['.js', '.cjs', '.mjs', '.ts', '.tsx', '.jsx'],
+      extension: nycOptions.extension || [
+        '.js',
+        '.cjs',
+        '.mjs',
+        '.ts',
+        '.tsx',
+        '.jsx'
+      ],
       all: nycOptions.all
     }