[New] Add no-arrow-function-lifecycle rule

CHANGELOG.md

@@ -7,8 +7,10 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 
 ### Added
 * [`no-unused-class-component-methods`]: Handle unused class component methods ([#2166][] @jakeleventhal @pawelnvk)
+* add [`no-arrow-function-lifecycle`] ([#1980][] @ngtan)
 
 [#2166]: https://github.com/yannickcr/eslint-plugin-react/pull/2166
+[#1980]: https://github.com/yannickcr/eslint-plugin-react/pull/1980
 
 ## [7.26.1] - 2021.09.29
 
@@ -3465,6 +3467,7 @@ If you're still not using React 15 you can keep the old behavior by setting the
 [`no-access-state-in-setstate`]: docs/rules/no-access-state-in-setstate.md
 [`no-adjacent-inline-elements`]: docs/rules/no-adjacent-inline-elements.md
 [`no-array-index-key`]: docs/rules/no-array-index-key.md
+[`no-arrow-function-lifecycle`]: docs/rules/no-arrow-function-lifecycle.md
 [`no-children-prop`]: docs/rules/no-children-prop.md
 [`no-comment-textnodes`]: docs/rules/jsx-no-comment-textnodes.md
 [`no-danger-with-children`]: docs/rules/no-danger-with-children.md

README.md

@@ -135,6 +135,7 @@ Enable the rules that you would like to use.
 |  |  | [react/no-access-state-in-setstate](docs/rules/no-access-state-in-setstate.md) | Reports when this.state is accessed within setState |
 |  |  | [react/no-adjacent-inline-elements](docs/rules/no-adjacent-inline-elements.md) | Prevent adjacent inline elements not separated by whitespace. |
 |  |  | [react/no-array-index-key](docs/rules/no-array-index-key.md) | Prevent usage of Array index in keys |
+|  | 🔧 | [react/no-arrow-function-lifecycle](docs/rules/no-arrow-function-lifecycle.md) | Lifecycle methods should be methods on the prototype, not class fields |
 | ✔ |  | [react/no-children-prop](docs/rules/no-children-prop.md) | Prevent passing of children as props. |
 |  |  | [react/no-danger](docs/rules/no-danger.md) | Prevent usage of dangerous JSX props |
 | ✔ |  | [react/no-danger-with-children](docs/rules/no-danger-with-children.md) | Report when a DOM element is using both children and dangerouslySetInnerHTML |

docs/rules/no-arrow-function-lifecycle.md

@@ -0,0 +1,41 @@
+# Lifecycle methods should be methods on the prototype, not class fields (react/no-arrow-function-lifecycle)
+
+It is not neccessary to use arrow function for lifecycle methods. This makes things harder to test, conceptually less performant (although in practice, performance will not be affected, since most engines will optimize efficiently), and can break hot reloading patterns.
+
+## Rule Details
+
+The following patterns are considered warnings:
+
+```jsx
+class Hello extends React.Component {
+  render = () => {
+    return <div />;
+  }
+}
+
+var AnotherHello = createReactClass({
+  render: () => {
+    return <div />;
+  },
+});
+```
+
+The following patterns are **not** considered warnings:
+
+```jsx
+class Hello extends React.Component {
+  render() {
+    return <div />;
+  }
+}
+
+var AnotherHello = createReactClass({
+  render() {
+    return <div />;
+  },
+});
+
+```
+## When Not To Use It
+
+If you don't care about performance of your application or conceptual correctness of class property placement, you can disable this rule.

index.js

@@ -57,6 +57,7 @@ const allRules = {
   'no-access-state-in-setstate': require('./lib/rules/no-access-state-in-setstate'),
   'no-adjacent-inline-elements': require('./lib/rules/no-adjacent-inline-elements'),
   'no-array-index-key': require('./lib/rules/no-array-index-key'),
+  'no-arrow-function-lifecycle': require('./lib/rules/no-arrow-function-lifecycle'),
   'no-children-prop': require('./lib/rules/no-children-prop'),
   'no-danger': require('./lib/rules/no-danger'),
   'no-danger-with-children': require('./lib/rules/no-danger-with-children'),

lib/rules/no-arrow-function-lifecycle.js

@@ -0,0 +1,80 @@
+/**
+ * @fileoverview Lifecycle methods should be methods on the prototype, not class fields
+ * @author Tan Nguyen
+ */
+
+'use strict';
+
+const values = require('object.values');
+
+const Components = require('../util/Components');
+const astUtil = require('../util/ast');
+const docsUrl = require('../util/docsUrl');
+const lifecycleMethods = require('../util/lifecycleMethods');
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'Lifecycle methods should be methods on the prototype, not class fields',
+      category: 'Best Practices',
+      recommended: false,
+      url: docsUrl('no-arrow-function-lifecycle')
+    },
+    schema: [],
+    fixable: 'code'
+  },
+
+  create: Components.detect((context, components, utils) => {
+    function getText(node) {
+      const params = node.value.params.map((p) => p.name);
+
+      if (node.type === 'Property') {
+        return `: function(${params.join(', ')}) `;
+      }
+
+      if (node.type === 'ClassProperty') {
+        return `(${params.join(', ')}) `;
+      }
+
+      return null;
+    }
+
+    /**
+     * @param {Array} properties list of component properties
+     */
+    function reportNoArrowFunctionLifecycle(properties) {
+      properties.forEach((node) => {
+        const propertyName = astUtil.getPropertyName(node);
+        const nodeType = node.value.type;
+        const isLifecycleMethod = (
+          node.static && !utils.isES5Component(node)
+            ? lifecycleMethods.static
+            : lifecycleMethods.instance
+        ).indexOf(propertyName) > -1;
+
+        if (nodeType === 'ArrowFunctionExpression' && isLifecycleMethod) {
+          const range = [node.key.range[1], node.value.body.range[0]];
+          const text = getText(node);
+
+          context.report({
+            node,
+            message: '{{propertyName}} is a React lifecycle method, and should not be an arrow function or in a class field. Use an instance method instead.',
+            data: {
+              propertyName
+            },
+            fix: (fixer) => fixer.replaceTextRange(range, text)
+          });
+        }
+      });
+    }
+
+    return {
+      'Program:exit'() {
+        values(components.list()).forEach((component) => {
+          const properties = astUtil.getComponentProperties(component.node);
+          reportNoArrowFunctionLifecycle(properties);
+        });
+      }
+    };
+  })
+};

lib/rules/no-typos.js

@@ -8,29 +8,13 @@ const PROP_TYPES = Object.keys(require('prop-types'));
 const Components = require('../util/Components');
 const docsUrl = require('../util/docsUrl');
 const report = require('../util/report');
+const lifecycleMethods = require('../util/lifecycleMethods');
 
 // ------------------------------------------------------------------------------
 // Rule Definition
 // ------------------------------------------------------------------------------
 
 const STATIC_CLASS_PROPERTIES = ['propTypes', 'contextTypes', 'childContextTypes', 'defaultProps'];
-const STATIC_LIFECYCLE_METHODS = ['getDerivedStateFromProps'];
-const LIFECYCLE_METHODS = [
-  'getDerivedStateFromProps',
-  'componentWillMount',
-  'UNSAFE_componentWillMount',
-  'componentDidMount',
-  'componentWillReceiveProps',
-  'UNSAFE_componentWillReceiveProps',
-  'shouldComponentUpdate',
-  'componentWillUpdate',
-  'UNSAFE_componentWillUpdate',
-  'getSnapshotBeforeUpdate',
-  'componentDidUpdate',
-  'componentDidCatch',
-  'componentWillUnmount',
-  'render'
-];
 
 const messages = {
   typoPropTypeChain: 'Typo in prop type chain qualifier: {{name}}',
@@ -167,7 +151,7 @@ module.exports = {
         return;
       }
 
-      STATIC_LIFECYCLE_METHODS.forEach((method) => {
+      lifecycleMethods.static.forEach((method) => {
         if (!node.static && nodeKeyName.toLowerCase() === method.toLowerCase()) {
           report(context, messages.staticLifecycleMethod, 'staticLifecycleMethod', {
             node,
@@ -178,7 +162,7 @@ module.exports = {
         }
       });
 
-      LIFECYCLE_METHODS.forEach((method) => {
+      lifecycleMethods.instance.concat(lifecycleMethods.static).forEach((method) => {
         if (method.toLowerCase() === nodeKeyName.toLowerCase() && method !== nodeKeyName) {
           report(context, messages.typoLifecycleMethod, 'typoLifecycleMethod', {
             node,

lib/util/lifecycleMethods.js

@@ -0,0 +1,30 @@
+/**
+ * @fileoverview lifecycle methods
+ * @author Tan Nguyen
+ */
+
+'use strict';
+
+module.exports = {
+  instance: [
+    'getDefaultProps',
+    'getInitialState',
+    'getChildContext',
+    'componentWillMount',
+    'UNSAFE_componentWillMount',
+    'componentDidMount',
+    'componentWillReceiveProps',
+    'UNSAFE_componentWillReceiveProps',
+    'shouldComponentUpdate',
+    'componentWillUpdate',
+    'UNSAFE_componentWillUpdate',
+    'getSnapshotBeforeUpdate',
+    'componentDidUpdate',
+    'componentDidCatch',
+    'componentWillUnmount',
+    'render'
+  ],
+  static: [
+    'getDerivedStateFromProps'
+  ]
+};