7846/use property initializer syntax

CHANGELOG.md

@@ -14,6 +14,7 @@
 ### Chore & Maintenance
 
 - `[*]` Make sure to include `d.ts` files in the tarball when building ([#8086](https://github.com/facebook/jest/pull/8086))
+- `[*]` Use property initializer syntax in Jest codebase [#8117](https://github.com/facebook/jest/pull/8117)
 
 ### Performance
 

babel.config.js

@@ -21,6 +21,7 @@ module.exports = {
   plugins: [
     ['@babel/plugin-transform-modules-commonjs', {allowTopLevelThis: true}],
     '@babel/plugin-transform-strict-mode',
+    '@babel/plugin-proposal-class-properties',
   ],
   presets: [
     [

e2e/__tests__/__snapshots__/consoleAfterTeardown.test.ts.snap

@@ -15,6 +15,6 @@ PASS __tests__/console.test.js
       15 | });
       16 | 
 
-      at BufferedConsole.log (../../packages/jest-console/build/BufferedConsole.js:180:10)
+      at BufferedConsole.log (../../packages/jest-console/build/BufferedConsole.js:199:10)
       at log (__tests__/console.test.js:13:13)
 `;

e2e/__tests__/__snapshots__/moduleNameMapper.test.ts.snap

@@ -30,6 +30,6 @@ FAIL __tests__/index.js
       12 | module.exports = () => 'test';
       13 | 
 
-      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:435:17)
+      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:455:17)
       at Object.require (index.js:10:1)
 `;

e2e/__tests__/__snapshots__/resolveNoFileExtensions.test.ts.snap

@@ -33,6 +33,6 @@ FAIL __tests__/test.js
         |                  ^
       4 | 
 
-      at Resolver.resolveModule (../../packages/jest-resolve/build/index.js:202:17)
+      at Resolver.resolveModule (../../packages/jest-resolve/build/index.js:222:17)
       at Object.require (index.js:3:18)
 `;

examples/enzyme/CheckboxWithLabel.js

@@ -3,18 +3,13 @@
 import React from 'react';
 
 export default class CheckboxWithLabel extends React.Component {
-  constructor(props) {
-    super(props);
-    this.state = {isChecked: false};
+  state = {
+    isChecked: false,
+  };
 
-    // bind manually because React class components don't auto-bind
-    // http://facebook.github.io/react/blog/2015/01/27/react-v0.13.0-beta-1.html#autobinding
-    this.onChange = this.onChange.bind(this);
-  }
-
-  onChange() {
+  onChange = () => {
     this.setState({isChecked: !this.state.isChecked});
-  }
+  };
 
   render() {
     return (

examples/react-testing-library/CheckboxWithLabel.js

@@ -6,15 +6,11 @@ export default class CheckboxWithLabel extends React.Component {
   constructor(props) {
     super(props);
     this.state = {isChecked: false};
-
-    // bind manually because React class components don't auto-bind
-    // http://facebook.github.io/react/blog/2015/01/27/react-v0.13.0-beta-1.html#autobinding
-    this.onChange = this.onChange.bind(this);
   }
 
-  onChange() {
+  onChange = () => {
     this.setState({isChecked: !this.state.isChecked});
-  }
+  };
 
   render() {
     return (

examples/react/CheckboxWithLabel.js

@@ -6,15 +6,11 @@ export default class CheckboxWithLabel extends React.Component {
   constructor(props) {
     super(props);
     this.state = {isChecked: false};
-
-    // bind manually because React class components don't auto-bind
-    // http://facebook.github.io/react/blog/2015/01/27/react-v0.13.0-beta-1.html#autobinding
-    this.onChange = this.onChange.bind(this);
   }
 
-  onChange() {
+  onChange = () => {
     this.setState({isChecked: !this.state.isChecked});
-  }
+  };
 
   render() {
     return (

examples/snapshot/Link.react.js

@@ -11,21 +11,18 @@ export default class Link extends React.Component {
   constructor() {
     super();
 
-    this._onMouseEnter = this._onMouseEnter.bind(this);
-    this._onMouseLeave = this._onMouseLeave.bind(this);
-
     this.state = {
       class: STATUS.NORMAL,
     };
   }
 
-  _onMouseEnter() {
+  _onMouseEnter = () => {
     this.setState({class: STATUS.HOVERED});
-  }
+  };
 
-  _onMouseLeave() {
+  _onMouseLeave = () => {
     this.setState({class: STATUS.NORMAL});
-  }
+  };
 
   render() {
     return (

package.json

@@ -2,6 +2,7 @@
   "private": true,
   "devDependencies": {
     "@babel/core": "^7.3.4",
+    "@babel/plugin-proposal-class-properties": "^7.3.4",
     "@babel/plugin-transform-modules-commonjs": "^7.1.0",
     "@babel/plugin-transform-strict-mode": "^7.0.0",
     "@babel/preset-env": "^7.1.0",

packages/jest-core/src/TestSequencer.ts

@@ -32,11 +32,7 @@ type Cache = {
  * is called to store/update this information on the cache map.
  */
 export default class TestSequencer {
-  private _cache: Map<Context, Cache>;
-
-  constructor() {
-    this._cache = new Map();
-  }
+  private _cache: Map<Context, Cache> = new Map();
 
   _getCachePath(context: Context) {
     const {config} = context;

packages/jest-core/src/plugins/update_snapshots_interactive.ts

@@ -11,16 +11,11 @@ import {BaseWatchPlugin, JestHookSubscriber} from 'jest-watcher';
 import SnapshotInteractiveMode from '../SnapshotInteractiveMode';
 
 class UpdateSnapshotInteractivePlugin extends BaseWatchPlugin {
-  private _snapshotInteractiveMode: SnapshotInteractiveMode;
-  private _failedSnapshotTestAssertions: Array<AssertionLocation>;
-  isInternal: true;
-
-  constructor(options: {stdin: NodeJS.ReadStream; stdout: NodeJS.WriteStream}) {
-    super(options);
-    this._failedSnapshotTestAssertions = [];
-    this._snapshotInteractiveMode = new SnapshotInteractiveMode(this._stdout);
-    this.isInternal = true;
-  }
+  private _snapshotInteractiveMode: SnapshotInteractiveMode = new SnapshotInteractiveMode(
+    this._stdout,
+  );
+  private _failedSnapshotTestAssertions: Array<AssertionLocation> = [];
+  isInternal: true = true;
 
   getFailedSnapshotTestAssertions(
     testResults: AggregatedResult,

packages/jest-watcher/src/lib/Prompt.ts

@@ -29,13 +29,11 @@ export default class Prompt {
     this._onChange = () => {};
     this._onSuccess = () => {};
     this._onCancel = () => {};
-
-    this._onResize = this._onResize.bind(this);
   }
 
-  private _onResize() {
+  private _onResize = () => {
     this._onChange();
-  }
+  };
 
   enter(
     onChange: (pattern: string, options: ScrollOptions) => void,

yarn.lock

@@ -279,7 +279,7 @@
     "@babel/helper-remap-async-to-generator" "^7.1.0"
     "@babel/plugin-syntax-async-generators" "^7.2.0"
 
-"@babel/plugin-proposal-class-properties@^7.0.0":
+"@babel/plugin-proposal-class-properties@^7.0.0", "@babel/plugin-proposal-class-properties@^7.3.4":
   version "7.3.4"
   resolved "https://registry.yarnpkg.com/@babel/plugin-proposal-class-properties/-/plugin-proposal-class-properties-7.3.4.tgz#410f5173b3dc45939f9ab30ca26684d72901405e"
   integrity sha512-lUf8D3HLs4yYlAo8zjuneLvfxN7qfKv1Yzbj5vjqaqMJxgJA3Ipwp4VUJ+OrOdz53Wbww6ahwB8UhB2HQyLotA==