prefer-string-starts-ends-with: Remove check on String#match() (#1002)

Author: fisker

docs/rules/prefer-string-starts-ends-with.md

@@ -1,19 +1,29 @@
-# Prefer `String#startsWith()` & `String#endsWith()` over more complex alternatives
+# Prefer `String#startsWith()` & `String#endsWith()` over `RegExp#test()`
 
-There are several ways of checking whether a string starts or ends with a certain string, such as `string.indexOf('foo') === 0` or using a regex with `/^foo/` or `/foo$/`. ES2015 introduced simpler alternatives named [`String#startsWith()`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith) and [`String#endsWith()`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith). This rule enforces the use of those whenever possible.
+Prefer [`String#startsWith()`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith) and [`String#endsWith()`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith) over using a regex with `/^foo/` or `/foo$/`.
 
-This rule is partly fixable.
+This rule is fixable.
 
 ## Fail
 
 ```js
-/^bar/.test(foo);
-/bar$/.test(foo);
+const foo = /^bar/.test(baz);
+```
+
+```js
+const foo = /bar$/.test(baz);
 ```
 
 ## Pass
 
 ```js
-foo.startsWith('bar');
-foo.endsWith('bar');
+const foo = baz.startsWith('bar');
+```
+
+```js
+const foo = baz.endsWith('bar');
+```
+
+```js
+const foo = /^bar/i.test(baz);
 ```

readme.md

@@ -170,7 +170,7 @@ Configure it in `package.json`.
 - [prefer-spread](docs/rules/prefer-spread.md) - Prefer the spread operator over `Array.from()`. *(fixable)*
 - [prefer-string-replace-all](docs/rules/prefer-string-replace-all.md) - Prefer `String#replaceAll()` over regex searches with the global flag. *(fixable)*
 - [prefer-string-slice](docs/rules/prefer-string-slice.md) - Prefer `String#slice()` over `String#substr()` and `String#substring()`. *(partly fixable)*
-- [prefer-string-starts-ends-with](docs/rules/prefer-string-starts-ends-with.md) - Prefer `String#startsWith()` & `String#endsWith()` over more complex alternatives. *(partly fixable)*
+- [prefer-string-starts-ends-with](docs/rules/prefer-string-starts-ends-with.md) - Prefer `String#startsWith()` & `String#endsWith()` over `RegExp#test()`. *(fixable)*
 - [prefer-string-trim-start-end](docs/rules/prefer-string-trim-start-end.md) - Prefer `String#trimStart()` / `String#trimEnd()` over `String#trimLeft()` / `String#trimRight()`. *(fixable)*
 - [prefer-ternary](docs/rules/prefer-ternary.md) - Prefer ternary expressions over simple `if-else` statements. *(fixable)*
 - [prefer-type-error](docs/rules/prefer-type-error.md) - Enforce throwing `TypeError` in type checking conditions. *(fixable)*

rules/prefer-string-starts-ends-with.js

@@ -24,11 +24,6 @@ const regexTestSelector = [
 	'[callee.object.regex]'
 ].join('');
 
-const stringMatchSelector = [
-	methodSelector({name: 'match', length: 1}),
-	'[arguments.0.regex]'
-].join('');
-
 const checkRegex = ({pattern, flags}) => {
 	if (flags.includes('i') || flags.includes('m')) {
 		return;
@@ -97,18 +92,6 @@ const create = context => {
 					];
 				}
 			});
-		},
-		[stringMatchSelector](node) {
-			const {regex} = node.arguments[0];
-			const result = checkRegex(regex);
-			if (!result) {
-				return;
-			}
-
-			context.report({
-				node,
-				messageId: result.messageId
-			});
 		}
 	};
 };

test/prefer-string-starts-ends-with.js

@@ -45,8 +45,11 @@ test({
 		'startWith("bar")',
 		'foo()()',
 
-		...validRegex.map(re => `${re}.test(bar)`),
-		...validRegex.map(re => `bar.match(${re})`)
+		// `prefer-regexp-test` cases
+		'if (foo.match(/^foo/)) {}',
+		'if (/^foo/.exec(foo)) {}',
+
+		...validRegex.map(re => `${re}.test(bar)`)
 	],
 	invalid: [
 		...invalidRegex.map(re => {
@@ -120,17 +123,7 @@ test({
 				) {}
 			`,
 			errors: [{messageId: MESSAGE_STARTS_WITH}]
-		},
-
-		...invalidRegex.map(re => {
-			const code = `bar.match(${re})`;
-			const messageId = re.source.startsWith('^') ? MESSAGE_STARTS_WITH : MESSAGE_ENDS_WITH;
-			return {
-				code,
-				output: code,
-				errors: [{messageId}]
-			};
-		})
+		}
 	]
 });