Merge df713a9 into 7aa2dc4

docs/rules/prefer-set-has.md

@@ -0,0 +1,31 @@
+# Prefer `Set#has()` over `Array#includes()` when checking for existence or non-existence.
+
+[`Set#has()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/has) is faster than [`Array#includes()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes).
+
+This rule is fixable.
+
+## Fail
+
+```js
+const array = [1, 2, 3];
+function isExists(find) {
+	return array.includes(find);
+}
+```
+
+## Pass
+
+```js
+const set = new Set([1, 2, 3]);
+function isExists(find) {
+	return set.has(find);
+}
+```
+
+```js
+const array = [1, 2];
+function isExists(find) {
+	return array.includes(find);
+}
+array.push(3);
+```

index.js

@@ -57,6 +57,7 @@ module.exports = {
 				'unicorn/prefer-reflect-apply': 'error',
 				// TODO: Enable this by default when it's shipping in a Node.js LTS version.
 				'unicorn/prefer-replace-all': 'off',
+				'unicorn/prefer-set-has': 'error',
 				'unicorn/prefer-spread': 'error',
 				'unicorn/prefer-starts-ends-with': 'error',
 				'unicorn/prefer-string-slice': 'error',

readme.md

@@ -72,6 +72,7 @@ Configure it in `package.json`.
 			"unicorn/prefer-query-selector": "error",
 			"unicorn/prefer-reflect-apply": "error",
 			"unicorn/prefer-replace-all": "off",
+			"unicorn/prefer-set-has": "error",
 			"unicorn/prefer-spread": "error",
 			"unicorn/prefer-starts-ends-with": "error",
 			"unicorn/prefer-string-slice": "error",
@@ -126,6 +127,7 @@ Configure it in `package.json`.
 - [prefer-query-selector](docs/rules/prefer-query-selector.md) - Prefer `.querySelector()` over `.getElementById()`, `.querySelectorAll()` over `.getElementsByClassName()` and `.getElementsByTagName()`. *(partly fixable)*
 - [prefer-reflect-apply](docs/rules/prefer-reflect-apply.md) - Prefer `Reflect.apply()` over `Function#apply()`. *(fixable)*
 - [prefer-replace-all](docs/rules/prefer-replace-all.md) - Prefer `String#replaceAll()` over regex searches with the global flag. *(fixable)*
+- [prefer-set-has](docs/rules/prefer-set-has.md) - Prefer `Set#has()` over `Array#includes()` when checking for existence or non-existence. *(fixable)*
 - [prefer-spread](docs/rules/prefer-spread.md) - Prefer the spread operator over `Array.from()`. *(fixable)*
 - [prefer-starts-ends-with](docs/rules/prefer-starts-ends-with.md) - Prefer `String#startsWith()` & `String#endsWith()` over more complex alternatives.
 - [prefer-string-slice](docs/rules/prefer-string-slice.md) - Prefer `String#slice()` over `String#substr()` and `String#substring()`. *(partly fixable)*

rules/consistent-function-scoping.js

@@ -1,13 +1,10 @@
 'use strict';
 const getDocumentationUrl = require('./utils/get-documentation-url');
+const getReferences = require('./utils/get-references');
 
 const MESSAGE_ID_NAMED = 'named';
 const MESSAGE_ID_ANONYMOUS = 'anonymous';
 
-const getReferences = scope => scope.references.concat(
-	...scope.childScopes.map(scope => getReferences(scope))
-);
-
 const isSameScope = (scope1, scope2) =>
 	scope1 && scope2 && (scope1 === scope2 || scope1.block === scope2.block);
 

rules/prefer-event-key.js

@@ -2,11 +2,11 @@
 const getDocumentationUrl = require('./utils/get-documentation-url');
 const quoteString = require('./utils/quote-string');
 
-const keys = [
+const keys = new Set([
 	'keyCode',
 	'charCode',
 	'which'
-];
+]);
 
 // https://github.com/facebook/react/blob/b87aabd/packages/react-dom/src/events/getEventKey.js#L36
 // Only meta characters which can't be deciphered from `String.fromCharCode()`
@@ -173,7 +173,7 @@ const create = context => {
 		Property(node) {
 			// Destructured case
 			const propertyName = node.value && node.value.name;
-			if (!keys.includes(propertyName)) {
+			if (!keys.has(propertyName)) {
 				return;
 			}
 

rules/prefer-set-has.js

@@ -0,0 +1,97 @@
+'use strict';
+const getDocumentationUrl = require('./utils/get-documentation-url');
+const getReferences = require('./utils/get-references');
+
+const selector = [
+	':not(ExportNamedDeclaration)',
+	'>',
+	'VariableDeclaration',
+	'>',
+	'VariableDeclarator',
+	'[init.type="ArrayExpression"]',
+	'>',
+	'Identifier'
+].join('');
+
+const MESSAGE_ID = 'preferSetHas';
+
+const isIncludesCall = node => {
+	/* istanbul ignore next */
+	if (!node.parent || !node.parent.parent) {
+		return false;
+	}
+
+	const {type, optional, callee, arguments: parameters} = node.parent.parent;
+	return (
+		type === 'CallExpression' &&
+		!optional,
+		callee &&
+		callee.type === 'MemberExpression' &&
+		!callee.computed &&
+		callee.object === node &&
+		callee.property.type === 'Identifier' &&
+		callee.property.name === 'includes' &&
+		parameters.length === 1 &&
+		parameters[0].type !== 'SpreadElement'
+	);
+};
+
+const create = context => {
+	const scope = context.getScope();
+	const declarations = new Set();
+
+	return {
+		[selector]: node => {
+			declarations.add(node);
+		},
+		'Program:exit'() {
+			if (declarations.size === 0) {
+				return;
+			}
+
+			const references = getReferences(scope);
+			for (const declaration of declarations) {
+				declarations.delete(declaration);
+
+				const variable = references
+					.find(({identifier}) => identifier === declaration)
+					.resolved;
+				const nodes = variable.references
+					.map(({identifier}) => identifier)
+					.filter(node => node !== declaration);
+
+				if (
+					nodes.length > 0 &&
+					nodes.every(node => isIncludesCall(node))
+				) {
+					context.report({
+						node: declaration,
+						messageId: MESSAGE_ID,
+						data: {
+							name: declaration.name
+						},
+						fix: fixer => [
+							fixer.insertTextBefore(declaration.parent.init, 'new Set('),
+							fixer.insertTextAfter(declaration.parent.init, ')'),
+							...nodes.map(node => fixer.replaceText(node.parent.property, 'has'))
+						]
+					});
+				}
+			}
+		}
+	};
+};
+
+module.exports = {
+	create,
+	meta: {
+		type: 'suggestion',
+		docs: {
+			url: getDocumentationUrl(__filename)
+		},
+		fixable: 'code',
+		messages: {
+			[MESSAGE_ID]: '`{{name}}` should be a `Set`, and use `{{name}}.has()` to check existence or non-existence.'
+		}
+	}
+};

rules/utils/get-references.js

@@ -0,0 +1,10 @@
+'use strict';
+const {uniq} = require('lodash');
+
+const getReferences = scope => uniq(
+	scope.references.concat(
+		...scope.childScopes.map(scope => getReferences(scope))
+	)
+);
+
+module.exports = getReferences;