Merge pull request jsx-eslint#1462 from DianaSuvorova/i216

[destructuring-assignment] : new rule

Author: ljharb

Diff for: README.md

@@ -84,6 +84,7 @@ Finally, enable all of the rules that you would like to use.  Use [our preset](#
 
 * [react/boolean-prop-naming](docs/rules/boolean-prop-naming.md): Enforces consistent naming for boolean props
 * [react/default-props-match-prop-types](docs/rules/default-props-match-prop-types.md): Prevent extraneous defaultProps on components
+* [react/destructuring-assignment](docs/rules/destructuring-assignment.md): Rule enforces consistent usage of destructuring assignment in component
 * [react/display-name](docs/rules/display-name.md): Prevent missing `displayName` in a React component definition
 * [react/forbid-component-props](docs/rules/forbid-component-props.md): Forbid certain props on Components
 * [react/forbid-elements](docs/rules/forbid-elements.md): Forbid certain elements

Diff for: docs/rules/destructuring-assignment.md

@@ -0,0 +1,87 @@
+# Enforce consistent usage of destructuring assignment of props, state, and context (react/destructuring-assignment)
+
+Rule can be set to either of `always` or `never`;
+```js
+"react/destructuring-assignment": [<enabled>, 'always']
+```
+
+## Rule Details
+
+By default rule is set to `always` enforce destructuring assignment. The following patterns are considered warnings:
+
+```js
+const MyComponent = (props) => {
+  return (<div id={props.id} />)
+};
+```
+
+```js
+const Foo = class extends React.PureComponent {
+  render() {
+    return <div>{this.context.foo}</div>;
+  }
+};
+```
+
+Below pattern is correct:
+
+```js
+const MyComponent = ({id}) => {
+  return (<div id={id} />)
+};
+```
+
+```js
+const MyComponent = (props, context) => {
+  const { id } = props;
+  return (<div id={id} />)
+};
+```
+
+```js
+const Foo = class extends React.PureComponent {
+  render() {
+    const { title } = this.context;
+    return <div>{title}</div>;
+  }
+};
+```
+
+If rule is set to `never`, the following patterns are considered warning:
+
+```js
+const MyComponent = ({id}) => {
+  return (<div id={id} />)
+};
+```
+
+```js
+const MyComponent = (props) => {
+  const { id } = props;
+  return (<div id={id} />)
+};
+```
+
+```js
+const Foo = class extends React.PureComponent {
+  render() {
+    const { title } = this.state;
+    return <div>{title}</div>;
+  }
+};
+```
+
+and below pattern is correct:
+
+```js
+const MyComponent = (props) => {
+  return (<div id={props.id} />)
+};
+```
+
+```js
+const Foo = class extends React.PureComponent {
+  render() {
+    return <div>{this.state.title}</div>;
+  }
+};

Diff for: index.js

@@ -5,6 +5,7 @@ const has = require('has');
 const allRules = {
   'boolean-prop-naming': require('./lib/rules/boolean-prop-naming'),
   'default-props-match-prop-types': require('./lib/rules/default-props-match-prop-types'),
+  'destructuring-assignment': require('./lib/rules/destructuring-assignment'),
   'display-name': require('./lib/rules/display-name'),
   'forbid-component-props': require('./lib/rules/forbid-component-props'),
   'forbid-elements': require('./lib/rules/forbid-elements'),

Diff for: lib/rules/destructuring-assignment.js

@@ -0,0 +1,137 @@
+/**
+ * @fileoverview Enforce consistent usage of destructuring assignment of props, state, and context.
+ **/
+'use strict';
+
+const Components = require('../util/Components');
+
+const DEFAULT_OPTION = 'always';
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'Enforce consistent usage of destructuring assignment of props, state, and context',
+      category: 'Stylistic Issues',
+      recommended: false
+    },
+    schema: [{
+      type: 'string',
+      enum: [
+        'always',
+        'never'
+      ]
+    }]
+  },
+
+  create: Components.detect((context, components, utils) => {
+    const configuration = context.options[0] || DEFAULT_OPTION;
+
+
+    /**
+    * Checks if a prop is being assigned a value props.bar = 'bar'
+    * @param {ASTNode} node The AST node being checked.
+    * @returns {Boolean}
+    */
+
+    function isAssignmentToProp(node) {
+      return (
+        node.parent &&
+        node.parent.type === 'AssignmentExpression' &&
+        node.parent.left === node
+      );
+    }
+    /**
+     * @param {ASTNode} node We expect either an ArrowFunctionExpression,
+     *   FunctionDeclaration, or FunctionExpression
+     */
+    function handleStatelessComponent(node) {
+      const destructuringProps = node.params && node.params[0] && node.params[0].type === 'ObjectPattern';
+      const destructuringContext = node.params && node.params[1] && node.params[1].type === 'ObjectPattern';
+
+      if (destructuringProps && components.get(node) && configuration === 'never') {
+        context.report({
+          node: node,
+          message: 'Must never use destructuring props assignment in SFC argument'
+        });
+      } else if (destructuringContext && components.get(node) && configuration === 'never') {
+        context.report({
+          node: node,
+          message: 'Must never use destructuring context assignment in SFC argument'
+        });
+      }
+    }
+
+    function handleSFCUsage(node) {
+      // props.aProp || context.aProp
+      const isPropUsed = (node.object.name === 'props' || node.object.name === 'context') && !isAssignmentToProp(node);
+      if (isPropUsed && configuration === 'always') {
+        context.report({
+          node: node,
+          message: `Must use destructuring ${node.object.name} assignment`
+        });
+      }
+    }
+
+    function handleClassUsage(node) {
+      // this.props.Aprop || this.context.aProp || this.state.aState
+      const isPropUsed = (node.object.type === 'MemberExpression' && node.object.object.type === 'ThisExpression' &&
+        (node.object.property.name === 'props' || node.object.property.name === 'context' || node.object.property.name === 'state') &&
+        node.object.type === 'MemberExpression'
+      );
+
+      if (isPropUsed && configuration === 'always') {
+        context.report({
+          node: node,
+          message: `Must use destructuring ${node.object.property.name} assignment`
+        });
+      }
+    }
+
+    return {
+
+      FunctionDeclaration: handleStatelessComponent,
+
+      ArrowFunctionExpression: handleStatelessComponent,
+
+      FunctionExpression: handleStatelessComponent,
+
+      MemberExpression: function(node) {
+        const SFCComponent = components.get(context.getScope(node).block);
+        const classComponent = utils.getParentComponent(node);
+        if (SFCComponent) {
+          handleSFCUsage(node);
+        }
+        if (classComponent) {
+          handleClassUsage(node, classComponent);
+        }
+      },
+
+      VariableDeclarator: function(node) {
+        const classComponent = utils.getParentComponent(node);
+        const SFCComponent = components.get(context.getScope(node).block);
+
+        const destructuring = (node.init && node.id && node.id.type === 'ObjectPattern');
+        // let {foo} = props;
+        const destructuringSFC = destructuring && (node.init.name === 'props' || node.init.name === 'context');
+        // let {foo} = this.props;
+        const destructuringClass = destructuring && node.init.object && node.init.object.type === 'ThisExpression' && (
+          node.init.property.name === 'props' || node.init.property.name === 'context' || node.init.property.name === 'state'
+        );
+
+        if (SFCComponent && destructuringSFC && configuration === 'never') {
+          context.report({
+            node: node,
+            message: `Must never use destructuring ${node.init.name} assignment`
+          });
+        }
+
+        if (classComponent && destructuringClass && configuration === 'never') {
+          context.report({
+            node: node,
+            message: `Must never use destructuring ${node.init.property.name} assignment`
+          });
+        }
+      }
+    };
+  })
+};