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Add regexp/prefer-quantifier rule (#24)
* Add `regexp/prefer-quantifier` rule * Add testcases * Add testcases
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‎README.md

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@@ -92,6 +92,7 @@ The rules with the following star :star: are included in the `plugin:regexp/reco
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| [regexp/no-useless-two-nums-quantifier](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-useless-two-nums-quantifier.html) | disallow unnecessary `{n,m}` quantifier | :star: |
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| [regexp/prefer-d](https://ota-meshi.github.io/eslint-plugin-regexp/rules/prefer-d.html) | enforce using `\d` | :star::wrench: |
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| [regexp/prefer-plus-quantifier](https://ota-meshi.github.io/eslint-plugin-regexp/rules/prefer-plus-quantifier.html) | enforce using `+` quantifier | :star::wrench: |
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| [regexp/prefer-quantifier](https://ota-meshi.github.io/eslint-plugin-regexp/rules/prefer-quantifier.html) | enforce using quantifier | :wrench: |
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| [regexp/prefer-question-quantifier](https://ota-meshi.github.io/eslint-plugin-regexp/rules/prefer-question-quantifier.html) | enforce using `?` quantifier | :star::wrench: |
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| [regexp/prefer-star-quantifier](https://ota-meshi.github.io/eslint-plugin-regexp/rules/prefer-star-quantifier.html) | enforce using `*` quantifier | :star::wrench: |
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| [regexp/prefer-t](https://ota-meshi.github.io/eslint-plugin-regexp/rules/prefer-t.html) | enforce using `\t` | :star::wrench: |

‎docs/rules/README.md

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@@ -24,6 +24,7 @@ The rules with the following star :star: are included in the `plugin:regexp/reco
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| [regexp/no-useless-two-nums-quantifier](./no-useless-two-nums-quantifier.md) | disallow unnecessary `{n,m}` quantifier | :star: |
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| [regexp/prefer-d](./prefer-d.md) | enforce using `\d` | :star::wrench: |
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| [regexp/prefer-plus-quantifier](./prefer-plus-quantifier.md) | enforce using `+` quantifier | :star::wrench: |
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| [regexp/prefer-quantifier](./prefer-quantifier.md) | enforce using quantifier | :wrench: |
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| [regexp/prefer-question-quantifier](./prefer-question-quantifier.md) | enforce using `?` quantifier | :star::wrench: |
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| [regexp/prefer-star-quantifier](./prefer-star-quantifier.md) | enforce using `*` quantifier | :star::wrench: |
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| [regexp/prefer-t](./prefer-t.md) | enforce using `\t` | :star::wrench: |

‎docs/rules/prefer-quantifier.md

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---
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pageClass: "rule-details"
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sidebarDepth: 0
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title: "regexp/prefer-quantifier"
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description: "enforce using quantifier"
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---
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# regexp/prefer-quantifier
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> enforce using quantifier
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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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This rule is aimed to use quantifiers instead of consecutive characters in regular expressions.
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<eslint-code-block fix>
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```js
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/* eslint regexp/prefer-quantifier: "error" */
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/* ✓ GOOD */
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var foo = /\d{4}-\d{2}-\d{2}/;
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/* ✗ BAD */
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var foo = /\d\d\d\d-\d\d-\d\d/;
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```
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</eslint-code-block>
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## :wrench: Options
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Nothing.
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## :mag: Implementation
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- [Rule source](https://github.com/ota-meshi/eslint-plugin-regexp/blob/master/lib/rules/prefer-quantifier.ts)
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- [Test source](https://github.com/ota-meshi/eslint-plugin-regexp/blob/master/tests/lib/rules/prefer-quantifier.ts)

‎lib/rules/match-any.ts

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@@ -65,6 +65,7 @@ export default createRule("match-any", {
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minItems: 1,
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},
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},
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additionalProperties: false,
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},
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],
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messages: {

‎lib/rules/prefer-quantifier.ts

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import type { Expression } from "estree"
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import type { RegExpVisitor } from "regexpp/visitor"
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import type { Character, CharacterSet, Quantifier } from "regexpp/ast"
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import {
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createRule,
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defineRegexpVisitor,
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getRegexpRange,
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isDigit,
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isLetter,
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} from "../utils"
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class CharBuffer {
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public target: CharacterSet | Character
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public min: number
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public max: number
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public elements: (CharacterSet | Character | Quantifier)[]
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public equalChar: (element: CharacterSet | Character) => boolean
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public constructor(
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element: CharacterSet | Character | Quantifier,
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target: CharacterSet | Character,
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) {
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this.target = target
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this.elements = [element]
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if (element.type === "Quantifier") {
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this.min = element.min
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this.max = element.max
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} else {
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this.min = 1
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this.max = 1
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}
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if (target.type === "CharacterSet") {
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if (target.kind === "any") {
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this.equalChar = (e) =>
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e.type === "CharacterSet" && e.kind === "any"
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} else if (target.kind === "property") {
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this.equalChar = (e) =>
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e.type === "CharacterSet" &&
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e.kind === "property" &&
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e.key === target.key &&
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e.value === target.value &&
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e.negate === target.negate
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} else {
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// Escape
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this.equalChar = (e) =>
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e.type === "CharacterSet" &&
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e.kind === target.kind &&
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e.negate === target.negate
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}
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} else {
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this.equalChar = (e) =>
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e.type === "Character" && e.value === target.value
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}
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}
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public addElement(element: CharacterSet | Character | Quantifier) {
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this.elements.push(element)
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if (element.type === "Quantifier") {
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this.min += element.min
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this.max += element.max
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} else {
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this.min += 1
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this.max += 1
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}
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}
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public isValid(): boolean {
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if (this.elements.length < 2) {
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return true
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}
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let charKind: "digit" | "letter" | null = null
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for (const element of this.elements) {
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if (element.type === "Character") {
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if (charKind == null) {
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if (isDigit(element.value)) {
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charKind = "digit"
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} else if (isLetter(element.value)) {
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charKind = "letter"
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} else {
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return false
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}
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}
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} else {
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return false
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}
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}
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if (
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// It is valid when the same numbers are consecutive.
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charKind === "digit" ||
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// It is valid when the same letter character continues twice.
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(charKind === "letter" && this.elements.length <= 2)
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) {
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return true
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}
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return false
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}
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public getQuantifier(): string {
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if (this.min === 0 && this.max === Number.POSITIVE_INFINITY) {
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return "*"
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} else if (this.min === 1 && this.max === Number.POSITIVE_INFINITY) {
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return "+"
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} else if (this.min === 0 && this.max === 1) {
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return "?"
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} else if (this.min === this.max) {
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return `{${this.min}}`
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} else if (this.max === Number.POSITIVE_INFINITY) {
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return `{${this.min},}`
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}
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return `{${this.min},${this.max}}`
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}
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}
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export default createRule("prefer-quantifier", {
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meta: {
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docs: {
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description: "enforce using quantifier",
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// TODO In the major version, it will be changed to "recommended".
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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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messages: {
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unexpected:
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'Unexpected consecutive same {{type}}. Use "{{quantifier}}" instead.',
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},
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type: "suggestion", // "problem",
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},
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create(context) {
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const sourceCode = context.getSourceCode()
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/**
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* Create visitor
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* @param node
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*/
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function createVisitor(node: Expression): RegExpVisitor.Handlers {
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return {
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onAlternativeEnter(aNode) {
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let charBuffer: CharBuffer | null = null
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for (const element of aNode.elements) {
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let target: CharacterSet | Character
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if (
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element.type === "CharacterSet" ||
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element.type === "Character"
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) {
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target = element
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} else if (element.type === "Quantifier") {
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if (
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element.element.type === "CharacterSet" ||
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element.element.type === "Character"
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) {
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target = element.element
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} else {
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if (charBuffer) {
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validateBuffer(charBuffer)
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charBuffer = null
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}
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continue
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}
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} else {
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if (charBuffer) {
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validateBuffer(charBuffer)
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charBuffer = null
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}
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continue
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}
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if (charBuffer) {
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if (charBuffer.equalChar(target)) {
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charBuffer.addElement(element)
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continue
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}
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validateBuffer(charBuffer)
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}
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charBuffer = new CharBuffer(element, target)
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}
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if (charBuffer) {
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validateBuffer(charBuffer)
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charBuffer = null
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}
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/**
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* Validate
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*/
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function validateBuffer(buffer: CharBuffer) {
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if (buffer.isValid()) {
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return
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}
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const firstRange = getRegexpRange(
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sourceCode,
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node,
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buffer.elements[0],
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)
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const lastRange = getRegexpRange(
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sourceCode,
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node,
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buffer.elements[buffer.elements.length - 1],
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)
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let range: [number, number] | null = null
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if (firstRange && lastRange) {
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range = [firstRange[0], lastRange[1]]
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}
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context.report({
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node,
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loc: range
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? {
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start: sourceCode.getLocFromIndex(
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range[0],
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),
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end: sourceCode.getLocFromIndex(range[1]),
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}
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: undefined,
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messageId: "unexpected",
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data: {
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type:
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buffer.target.type === "Character"
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? "characters"
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: "character sets",
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quantifier: buffer.getQuantifier(),
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},
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fix(fixer) {
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if (range == null) {
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return null
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}
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return fixer.replaceTextRange(
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range,
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buffer.target.raw + buffer.getQuantifier(),
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)
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},
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})
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}
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},
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}
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}
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return defineRegexpVisitor(context, {
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createVisitor,
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})
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},
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})

‎lib/utils/rules.ts

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@@ -12,6 +12,7 @@ import noUselessExactlyQuantifier from "../rules/no-useless-exactly-quantifier"
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import noUselessTwoNumsQuantifier from "../rules/no-useless-two-nums-quantifier"
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import preferD from "../rules/prefer-d"
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import preferPlusQuantifier from "../rules/prefer-plus-quantifier"
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import preferQuantifier from "../rules/prefer-quantifier"
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import preferQuestionQuantifier from "../rules/prefer-question-quantifier"
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import preferStarQuantifier from "../rules/prefer-star-quantifier"
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import preferT from "../rules/prefer-t"
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noUselessTwoNumsQuantifier,
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preferD,
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preferPlusQuantifier,
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preferQuantifier,
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preferQuestionQuantifier,
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preferStarQuantifier,
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preferT,

‎lib/utils/unicode.ts

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export function isDigit(codePoint: number): boolean {
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return isCodePointInRange(codePoint, CP_RANGE_DIGIT)
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}
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/**
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* Checks if the given code point is letter.
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* @param codePoint The code point to check
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* @returns {boolean} `true` if the given code point is letter.
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*/
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export function isLetter(codePoint: number): boolean {
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return (
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isCodePointInRange(codePoint, CP_RANGE_SMALL_LETTER) ||
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isCodePointInRange(codePoint, CP_RANGE_CAPITAL_LETTER)
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)
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}
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/**
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* Checks if the given code point is space.

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