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Add regexp/no-missing-g-flag rule (#474)
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‎README.md

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@@ -116,6 +116,7 @@ The rules with the following star :star: are included in the `plugin:regexp/reco
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| [regexp/no-invalid-regexp](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-invalid-regexp.html) | disallow invalid regular expression strings in `RegExp` constructors | :star: |
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| [regexp/no-lazy-ends](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-lazy-ends.html) | disallow lazy quantifiers at the end of an expression | :star: |
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| [regexp/no-misleading-unicode-character](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-misleading-unicode-character.html) | disallow multi-code-point characters in character classes and quantifiers | :wrench: |
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| [regexp/no-missing-g-flag](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-missing-g-flag.html) | disallow missing `g` flag in patterns used in `String#matchAll` and `String#replaceAll` | :wrench: |
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| [regexp/no-optional-assertion](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-optional-assertion.html) | disallow optional assertions | :star: |
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| [regexp/no-potentially-useless-backreference](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-potentially-useless-backreference.html) | disallow backreferences that reference a group that might not be matched | :star: |
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| [regexp/no-super-linear-backtracking](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-super-linear-backtracking.html) | disallow exponential and polynomial backtracking | :star::wrench: |

‎docs/rules/README.md

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| [regexp/no-invalid-regexp](./no-invalid-regexp.md) | disallow invalid regular expression strings in `RegExp` constructors | :star: |
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| [regexp/no-lazy-ends](./no-lazy-ends.md) | disallow lazy quantifiers at the end of an expression | :star: |
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| [regexp/no-misleading-unicode-character](./no-misleading-unicode-character.md) | disallow multi-code-point characters in character classes and quantifiers | :wrench: |
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| [regexp/no-missing-g-flag](./no-missing-g-flag.md) | disallow missing `g` flag in patterns used in `String#matchAll` and `String#replaceAll` | :wrench: |
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| [regexp/no-optional-assertion](./no-optional-assertion.md) | disallow optional assertions | :star: |
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| [regexp/no-potentially-useless-backreference](./no-potentially-useless-backreference.md) | disallow backreferences that reference a group that might not be matched | :star: |
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| [regexp/no-super-linear-backtracking](./no-super-linear-backtracking.md) | disallow exponential and polynomial backtracking | :star::wrench: |

‎docs/rules/no-missing-g-flag.md

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---
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pageClass: "rule-details"
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sidebarDepth: 0
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title: "regexp/no-missing-g-flag"
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description: "disallow missing `g` flag in patterns used in `String#matchAll` and `String#replaceAll`"
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---
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# regexp/no-missing-g-flag
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> disallow missing `g` flag in patterns used in `String#matchAll` and `String#replaceAll`
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- :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> ***This rule has not been released yet.*** </badge>
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- :wrench: The `--fix` option on the [command line](https://eslint.org/docs/user-guide/command-line-interface#fixing-problems) can automatically fix some of the problems reported by this rule.
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## :book: Rule Details
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When calling [`String#matchAll()`] and [`String#replaceAll()`] with a `RegExp` missing the global (`g`) flag, it will be a runtime error.
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This rule reports `RegExp`s missing the global (`g`) flag that cause these errors.
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<eslint-code-block fix>
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```js
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/* eslint regexp/no-missing-g-flag: "error" */
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const games = 'table football, foosball'
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const text = 'The quick brown fox jumps over the lazy dog. If the dog reacted, was it really lazy?';
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/* ✓ GOOD */
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var m = games.matchAll(/foo/g);
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var newText = text.replaceAll(/Dog/ig, 'cat');
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/* ✗ BAD */
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var m = games.matchAll(/foo/);
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var newText = text.replaceAll(/Dog/i, 'cat');
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```
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</eslint-code-block>
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## :wrench: Options
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```json
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{
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"regexp/no-missing-g-flag": ["error",
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{
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"strictTypes": true
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}
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]
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}
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```
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- `strictTypes` ... If `true`, strictly check the type of object to determine if the regex instance was used in `matchAll()` and `replaceAll()`. Default is `true`.
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This option is always on when using TypeScript.
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## :books: Further reading
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- [MDN Web Docs - String.prototype.matchAll()][`String#matchAll()`]
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- [MDN Web Docs - String.prototype.replaceAll()][`String#replaceAll()`]
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[`String#matchAll()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/matchAll
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[`String#replaceAll()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll
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## :mag: Implementation
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- [Rule source](https://github.com/ota-meshi/eslint-plugin-regexp/blob/master/lib/rules/no-missing-g-flag.ts)
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- [Test source](https://github.com/ota-meshi/eslint-plugin-regexp/blob/master/tests/lib/rules/no-missing-g-flag.ts)

‎lib/rules/no-missing-g-flag.ts

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import type { RegExpContext, UnparsableRegExpContext } from "../utils"
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import { createRule, defineRegexpVisitor } from "../utils"
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import type { ExpressionReference } from "../utils/ast-utils"
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import {
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extractExpressionReferences,
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isKnownMethodCall,
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} from "../utils/ast-utils"
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import { createTypeTracker } from "../utils/type-tracker"
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/**
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* Parse option
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*/
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function parseOption(
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userOption:
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| {
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strictTypes?: boolean
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}
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| undefined,
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) {
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let strictTypes = true
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if (userOption) {
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if (userOption.strictTypes != null) {
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strictTypes = userOption.strictTypes
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}
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}
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return {
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strictTypes,
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}
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}
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export default createRule("no-missing-g-flag", {
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meta: {
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docs: {
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description:
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"disallow missing `g` flag in patterns used in `String#matchAll` and `String#replaceAll`",
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category: "Possible Errors",
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// TODO Switch to recommended in the major version.
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// recommended: true,
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recommended: false,
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},
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fixable: "code",
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schema: [
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{
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type: "object",
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properties: {
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strictTypes: { type: "boolean" },
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},
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additionalProperties: false,
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},
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],
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messages: {
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missingGlobalFlag:
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"The pattern given to the argument of `String#{{method}}()` requires the `g` flag, but is missing it.",
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},
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type: "problem",
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},
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create(context) {
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const { strictTypes } = parseOption(context.options[0])
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const typeTracer = createTypeTracker(context)
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/** The logic of this rule */
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function visit(regexpContext: RegExpContext | UnparsableRegExpContext) {
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const { regexpNode, flags, flagsString } = regexpContext
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if (
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flags.global ||
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// We were unable to determine which flags were used.
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flagsString == null
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) {
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return
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}
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for (const ref of extractExpressionReferences(
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regexpNode,
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context,
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)) {
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verifyExpressionReference(ref, regexpContext)
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}
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}
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/**
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* Verify RegExp reference
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*/
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function verifyExpressionReference(
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ref: ExpressionReference,
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{
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regexpNode,
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fixReplaceFlags,
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flagsString,
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}: RegExpContext | UnparsableRegExpContext,
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): void {
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if (ref.type !== "argument") {
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// It is not used for function call arguments.
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return
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}
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const node = ref.callExpression
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if (
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// It is not specified in the first argument.
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node.arguments[0] !== ref.node ||
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// It is not replaceAll() and matchAll().
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!isKnownMethodCall(node, {
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matchAll: 1,
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replaceAll: 2,
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})
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) {
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return
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}
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if (
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strictTypes
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? !typeTracer.isString(node.callee.object)
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: !typeTracer.maybeString(node.callee.object)
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) {
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// The callee object is not a string.
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return
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}
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context.report({
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node: ref.node,
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messageId: "missingGlobalFlag",
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data: {
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method: node.callee.property.name,
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},
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fix: buildFixer(),
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})
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/** Build fixer */
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function buildFixer() {
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if (
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node.arguments[0] !== regexpNode ||
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((regexpNode.type === "NewExpression" ||
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regexpNode.type === "CallExpression") &&
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regexpNode.arguments[1] &&
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regexpNode.arguments[1].type !== "Literal")
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) {
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// It can only be safely auto-fixed if it is defined directly in the argument.
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return null
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}
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return fixReplaceFlags(`${flagsString!}g`, false)
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}
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}
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return defineRegexpVisitor(context, {
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createVisitor(regexpContext) {
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visit(regexpContext)
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return {}
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},
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visitInvalid: visit,
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visitUnknown: visit,
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})
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},
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})

‎lib/utils/rules.ts

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import noLazyEnds from "../rules/no-lazy-ends"
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import noLegacyFeatures from "../rules/no-legacy-features"
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import noMisleadingUnicodeCharacter from "../rules/no-misleading-unicode-character"
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import noMissingGFlag from "../rules/no-missing-g-flag"
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import noNonStandardFlag from "../rules/no-non-standard-flag"
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import noObscureRange from "../rules/no-obscure-range"
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import noOctal from "../rules/no-octal"
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noLazyEnds,
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noLegacyFeatures,
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noMisleadingUnicodeCharacter,
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noMissingGFlag,
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noNonStandardFlag,
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noObscureRange,
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noOctal,

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