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Add prefer-regexp-test rule (#970)
Co-authored-by: Sindre Sorhus <[email protected]>
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‎docs/rules/prefer-regexp-test.md‎

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# Prefer `RegExp#test()` over `String#match()` and `RegExp#exec()`
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When you want to know whether a pattern is found in a string, use [`RegExp#test()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/test) instead of [`String#match()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/match) and [`RegExp#exec()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/exec).
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This rule is fixable.
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## Fail
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```js
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if (string.match(/unicorn/)) {}
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```
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```js
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if (/unicorn/.exec(string)) {}
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```
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## Pass
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```js
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if (/unicorn/.test(string)) {}
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```

‎index.js‎

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@@ -97,6 +97,7 @@ module.exports = {
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'unicorn/prefer-optional-catch-binding': 'error',
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'unicorn/prefer-query-selector': 'error',
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'unicorn/prefer-reflect-apply': 'error',
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'unicorn/prefer-regexp-test': 'error',
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'unicorn/prefer-set-has': 'error',
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'unicorn/prefer-spread': 'error',
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// TODO: Enable this by default when targeting Node.js 16.

‎readme.md‎

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@@ -89,6 +89,7 @@ Configure it in `package.json`.
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"unicorn/prefer-optional-catch-binding": "error",
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"unicorn/prefer-query-selector": "error",
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"unicorn/prefer-reflect-apply": "error",
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"unicorn/prefer-regexp-test": "error",
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"unicorn/prefer-set-has": "error",
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"unicorn/prefer-spread": "error",
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"unicorn/prefer-string-replace-all": "off",
@@ -162,6 +163,7 @@ Configure it in `package.json`.
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- [prefer-optional-catch-binding](docs/rules/prefer-optional-catch-binding.md) - Prefer omitting the `catch` binding parameter. *(fixable)*
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- [prefer-query-selector](docs/rules/prefer-query-selector.md) - Prefer `.querySelector()` over `.getElementById()`, `.querySelectorAll()` over `.getElementsByClassName()` and `.getElementsByTagName()`. *(partly fixable)*
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- [prefer-reflect-apply](docs/rules/prefer-reflect-apply.md) - Prefer `Reflect.apply()` over `Function#apply()`. *(fixable)*
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- [prefer-regexp-test](docs/rules/prefer-regexp-test.md) - Prefer `RegExp#test()` over `String#match()` and `RegExp#exec()`. *(fixable)*
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- [prefer-set-has](docs/rules/prefer-set-has.md) - Prefer `Set#has()` over `Array#includes()` when checking for existence or non-existence. *(fixable)*
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- [prefer-spread](docs/rules/prefer-spread.md) - Prefer the spread operator over `Array.from()`. *(fixable)*
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- [prefer-string-replace-all](docs/rules/prefer-string-replace-all.md) - Prefer `String#replaceAll()` over regex searches with the global flag. *(fixable)*

‎rules/prefer-regexp-test.js‎

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'use strict';
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const {isParenthesized} = require('eslint-utils');
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const getDocumentationUrl = require('./utils/get-documentation-url');
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const methodSelector = require('./utils/method-selector');
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const {isBooleanNode} = require('./utils/boolean');
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const shouldAddParenthesesToMemberExpressionObject = require('./utils/should-add-parentheses-to-member-expression-object');
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const MESSAGE_ID_REGEXP_EXEC = 'regexp-exec';
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const MESSAGE_ID_STRING_MATCH = 'string-match';
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const messages = {
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[MESSAGE_ID_REGEXP_EXEC]: 'Prefer `.test(…)` over `.exec(…)`.',
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[MESSAGE_ID_STRING_MATCH]: 'Prefer `RegExp#test(…)` over `String#match(…)`.'
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};
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const regExpExecCallSelector = methodSelector({
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name: 'exec',
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length: 1
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});
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const stringMatchCallSelector = methodSelector({
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name: 'match',
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length: 1
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});
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const create = context => {
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const sourceCode = context.getSourceCode();
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return {
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[regExpExecCallSelector](node) {
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if (!isBooleanNode(node)) {
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return;
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}
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node = node.callee.property;
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context.report({
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node,
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messageId: MESSAGE_ID_REGEXP_EXEC,
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fix: fixer => fixer.replaceText(node, 'test')
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});
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},
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[stringMatchCallSelector](node) {
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if (!isBooleanNode(node)) {
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return;
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}
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const regexpNode = node.arguments[0];
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if (regexpNode.type === 'Literal' && !regexpNode.regex) {
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return;
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}
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const stringNode = node.callee.object;
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context.report({
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node,
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messageId: MESSAGE_ID_STRING_MATCH,
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* fix(fixer) {
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yield fixer.replaceText(node.callee.property, 'test');
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let stringText = sourceCode.getText(stringNode);
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if (
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!isParenthesized(regexpNode, sourceCode) &&
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// Only `SequenceExpression` need add parentheses
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stringNode.type === 'SequenceExpression'
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) {
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stringText = `(${stringText})`;
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}
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yield fixer.replaceText(regexpNode, stringText);
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let regexpText = sourceCode.getText(regexpNode);
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if (
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!isParenthesized(stringNode, sourceCode) &&
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shouldAddParenthesesToMemberExpressionObject(regexpNode, sourceCode)
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) {
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regexpText = `(${regexpText})`;
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}
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// The nodes that pass `isBooleanNode` cannot have an ASI problem.
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yield fixer.replaceText(stringNode, regexpText);
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}
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});
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}
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};
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};
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module.exports = {
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create,
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meta: {
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type: 'suggestion',
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docs: {
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url: getDocumentationUrl(__filename)
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},
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fixable: 'code',
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messages
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}
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};

‎test/prefer-regexp-test.js‎

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import {outdent} from 'outdent';
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import {test} from './utils/test';
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test({
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valid: [
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'const bar = !re.test(foo)',
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// Not `boolean`
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'const matches = foo.match(re) || []',
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'const matches = foo.match(re)',
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'const matches = re.exec(foo)',
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'while (foo = re.exec(bar)) {}',
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'while ((foo = re.exec(bar))) {}',
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// Method not match
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'if (foo.notMatch(re)) {}',
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'if (re.notExec(foo)) {}',
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// Not `CallExpression`
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'if (foo.match) {}',
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'if (re.exec) {}',
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// Computed
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'if (foo[match](re)) {}',
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'if (re[exec](foo)) {}',
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'if (foo["match"](re)) {}',
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'if (re["exec"](foo)) {}',
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// Not `MemberExpression`
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'if (match(re)) {}',
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'if (exec(foo)) {}',
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// More/Less arguments
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'if (foo.match()) {}',
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'if (re.exec()) {}',
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'if (foo.match(re, another)) {}',
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'if (re.exec(foo, another)) {}',
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'if (foo.match(...[regexp])) {}',
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'if (re.exec(...[string])) {}',
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// Not regex
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'if (foo.match(1)) {}',
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'if (foo.match("1")) {}',
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'if (foo.match(null)) {}',
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'if (foo.match(1n)) {}',
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'if (foo.match(true)) {}'
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],
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invalid: []
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});
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test.visualize([
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// `String#match()`
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'const bar = !foo.match(re)',
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'const bar = Boolean(foo.match(re))',
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'if (foo.match(re)) {}',
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'const bar = foo.match(re) ? 1 : 2',
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'while (foo.match(re)) foo = foo.slice(1);',
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'do {foo = foo.slice(1)} while (foo.match(re));',
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'for (; foo.match(re); ) foo = foo.slice(1);',
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// `RegExp#exec()`
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'const bar = !re.exec(foo)',
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'const bar = Boolean(re.exec(foo))',
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'if (re.exec(foo)) {}',
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'const bar = re.exec(foo) ? 1 : 2',
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'while (re.exec(foo)) foo = foo.slice(1);',
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'do {foo = foo.slice(1)} while (re.exec(foo));',
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'for (; re.exec(foo); ) foo = foo.slice(1);',
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// Parentheses
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'if ((0, foo).match(re)) {}',
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'if ((0, foo).match((re))) {}',
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'if ((foo).match(re)) {}',
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'if ((foo).match((re))) {}',
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'if (foo.match(/re/)) {}',
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'if (foo.match(bar)) {}',
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'if (foo.match(bar.baz)) {}',
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'if (foo.match(bar.baz())) {}',
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'if (foo.match(new RegExp("re", "g"))) {}',
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'if (foo.match(new SomeRegExp())) {}',
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'if (foo.match(new SomeRegExp)) {}',
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'if (foo.match(bar?.baz)) {}',
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'if (foo.match(bar?.baz())) {}',
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'if (foo.match(bar || baz)) {}',
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outdent`
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async function a() {
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if (foo.match(await bar())) {}
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}
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`,
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'if ((foo).match(/re/)) {}',
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'if ((foo).match(new SomeRegExp)) {}',
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'if ((foo).match(bar?.baz)) {}',
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'if ((foo).match(bar?.baz())) {}',
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'if ((foo).match(bar || baz)) {}',
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outdent`
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async function a() {
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if ((foo).match(await bar())) {}
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}
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`,
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// Should not need handle ASI problem
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'if (foo.match([re][0])) {}',
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// Comments
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outdent`
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async function a() {
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if (
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/* 1 */ foo() /* 2 */
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./* 3 */ match /* 4 */ (
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/* 5 */ await /* 6 */ bar() /* 7 */
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,
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/* 8 */
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)
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) {}
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}
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`
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]);

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