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Add regexp/no-useless-range rule (#34)
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‎README.md

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@@ -91,6 +91,7 @@ The rules with the following star :star: are included in the `plugin:regexp/reco
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| [regexp/no-useless-backreference](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-useless-backreference.html) | disallow useless backreferences in regular expressions | |
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| [regexp/no-useless-character-class](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-useless-character-class.html) | disallow character class with one character | :wrench: |
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| [regexp/no-useless-exactly-quantifier](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-useless-exactly-quantifier.html) | disallow unnecessary exactly quantifier | :star: |
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| [regexp/no-useless-range](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-useless-range.html) | disallow unnecessary range of characters by using a hyphen | :wrench: |
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| [regexp/no-useless-non-greedy](https://ota-meshi.github.io/eslint-plugin-regexp/rules/no-useless-non-greedy.html) | disallow unnecessary quantifier non-greedy (`?`) | :wrench: |
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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: |

‎docs/rules/README.md

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@@ -23,6 +23,7 @@ The rules with the following star :star: are included in the `plugin:regexp/reco
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| [regexp/no-useless-backreference](./no-useless-backreference.md) | disallow useless backreferences in regular expressions | |
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| [regexp/no-useless-character-class](./no-useless-character-class.md) | disallow character class with one character | :wrench: |
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| [regexp/no-useless-exactly-quantifier](./no-useless-exactly-quantifier.md) | disallow unnecessary exactly quantifier | :star: |
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| [regexp/no-useless-range](./no-useless-range.md) | disallow unnecessary range of characters by using a hyphen | :wrench: |
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| [regexp/no-useless-non-greedy](./no-useless-non-greedy.md) | disallow unnecessary quantifier non-greedy (`?`) | :wrench: |
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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: |

‎docs/rules/no-useless-range.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-useless-range"
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description: "disallow unnecessary range of characters by using a hyphen"
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---
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# regexp/no-useless-range
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> disallow unnecessary range of characters by using a hyphen
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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 reports unnecessary range of characters by using a hyphen. e.g. `[a-a]`
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<eslint-code-block fix>
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```js
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/* eslint regexp/no-useless-range: "error" */
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/* ✓ GOOD */
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var foo = /[a]/
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var foo = /[ab]/
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/* ✗ BAD */
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var foo = /[a-a]/
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var foo = /[a-b]/
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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/no-useless-range.ts)
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- [Test source](https://github.com/ota-meshi/eslint-plugin-regexp/blob/master/tests/lib/rules/no-useless-range.ts)

‎lib/rules/no-useless-range.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 {
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createRule,
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defineRegexpVisitor,
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fixerApplyEscape,
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getRegexpLocation,
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getRegexpRange,
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} from "../utils"
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export default createRule("no-useless-range", {
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meta: {
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docs: {
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description:
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"disallow unnecessary range of characters by using a hyphen",
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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 unnecessary range of characters by using a hyphen.",
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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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onCharacterClassRangeEnter(ccrNode) {
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if (
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ccrNode.min.value !== ccrNode.max.value &&
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ccrNode.min.value + 1 !== ccrNode.max.value
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) {
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return
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}
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context.report({
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node,
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loc: getRegexpLocation(sourceCode, node, ccrNode),
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messageId: "unexpected",
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fix(fixer) {
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const range = getRegexpRange(
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sourceCode,
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node,
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ccrNode,
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)
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if (range == null) {
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return null
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}
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let text =
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ccrNode.min.value < ccrNode.max.value
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? ccrNode.min.raw + ccrNode.max.raw
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: ccrNode.min.raw
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const parent = ccrNode.parent
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const next =
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parent.elements[
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parent.elements.indexOf(ccrNode) + 1
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]
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if (
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next &&
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next.type === "Character" &&
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next.raw === "-"
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) {
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text += fixerApplyEscape("\\", node)
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}
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return fixer.replaceTextRange(range, text)
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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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@@ -11,6 +11,7 @@ import noOctal from "../rules/no-octal"
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import noUselessBackreference from "../rules/no-useless-backreference"
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import noUselessCharacterClass from "../rules/no-useless-character-class"
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import noUselessExactlyQuantifier from "../rules/no-useless-exactly-quantifier"
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import noUselessRange from "../rules/no-useless-range"
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import noUselessNonGreedy from "../rules/no-useless-non-greedy"
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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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noUselessBackreference,
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noUselessCharacterClass,
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noUselessExactlyQuantifier,
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noUselessRange,
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noUselessNonGreedy,
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noUselessTwoNumsQuantifier,
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preferD,

‎tests/lib/rules/no-useless-range.ts

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import { RuleTester } from "eslint"
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import rule from "../../../lib/rules/no-useless-range"
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const tester = new RuleTester({
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parserOptions: {
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ecmaVersion: 2020,
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sourceType: "module",
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},
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})
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tester.run("no-useless-range", rule as any, {
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valid: [`/[a]/`, `/[ab]/`, `/[a-c]/`],
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invalid: [
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{
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code: `/[a-a]/`,
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output: `/[a]/`,
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errors: [
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{
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message:
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"Unexpected unnecessary range of characters by using a hyphen.",
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line: 1,
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column: 3,
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},
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],
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},
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{
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code: `/[a-b]/`,
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output: `/[ab]/`,
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errors: [
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{
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message:
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"Unexpected unnecessary range of characters by using a hyphen.",
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line: 1,
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column: 3,
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},
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],
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},
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{
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code: `/[a-a-c-c]/`,
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output: `/[a\\-c]/`,
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errors: [
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{
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message:
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"Unexpected unnecessary range of characters by using a hyphen.",
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line: 1,
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column: 3,
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},
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{
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message:
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"Unexpected unnecessary range of characters by using a hyphen.",
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line: 1,
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column: 7,
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},
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],
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},
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{
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code: `/[a-abc]/`,
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output: `/[abc]/`,
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errors: [
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{
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message:
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"Unexpected unnecessary range of characters by using a hyphen.",
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line: 1,
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column: 3,
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},
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],
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},
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{
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code: `
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const s = "[a-a-c]"
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new RegExp(s)`,
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output: `
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const s = "[a\\\\-c]"
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new RegExp(s)`,
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errors: [
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"Unexpected unnecessary range of characters by using a hyphen.",
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],
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},
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{
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code: `
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const s = "[a-"+"a]"
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new RegExp(s)`,
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output: null,
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errors: [
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"Unexpected unnecessary range of characters by using a hyphen.",
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],
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},
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],
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})

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