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RebeccaStevensRebeccaStevens
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feat: new rule no-class-inheritance (#890)
fix #886
1 parent 579170c commit 53df2fd

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‎.github/workflows/semantic-pr.yml

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@@ -32,6 +32,7 @@ jobs:
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functional-parameters
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immutable-data
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no-classes
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no-class-inheritance
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no-conditional-statements
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no-expression-statements
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no-let

‎README.md

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@@ -135,11 +135,12 @@ The [below section](#rules) gives details on which rules are enabled by each rul
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### No Other Paradigms
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| Name                | Description | 💼 | ⚠️ | 🚫 | 🔧 | 💡 | 💭 | ❌ |
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| :------------------------------------------------------- | :------------------------------------------------------------------------ | :----------------------------------- | :-- | :---------------------------- | :-- | :-- | :-- | :-- |
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| [no-classes](docs/rules/no-classes.md) | Disallow classes. | ☑️ ✅ 🔒 ![badge-noOtherParadigms][] | | | | | | |
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| [no-mixed-types](docs/rules/no-mixed-types.md) | Restrict types so that only members of the same kind are allowed in them. | ☑️ ✅ 🔒 ![badge-noOtherParadigms][] | | ![badge-disableTypeChecked][] | | | 💭 | |
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| [no-this-expressions](docs/rules/no-this-expressions.md) | Disallow this access. | 🔒 ![badge-noOtherParadigms][] | | ☑️ ✅ | | | | |
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| Name                 | Description | 💼 | ⚠️ | 🚫 | 🔧 | 💡 | 💭 | ❌ |
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| :--------------------------------------------------------- | :------------------------------------------------------------------------ | :----------------------------------- | :-- | :---------------------------- | :-- | :-- | :-- | :-- |
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| [no-class-inheritance](docs/rules/no-class-inheritance.md) | Disallow inheritance in classes. | ☑️ ✅ 🔒 ![badge-noOtherParadigms][] | | | | | | |
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| [no-classes](docs/rules/no-classes.md) | Disallow classes. | ✅ 🔒 ![badge-noOtherParadigms][] | | ☑️ | | | | |
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| [no-mixed-types](docs/rules/no-mixed-types.md) | Restrict types so that only members of the same kind are allowed in them. | ☑️ ✅ 🔒 ![badge-noOtherParadigms][] | | ![badge-disableTypeChecked][] | | | 💭 | |
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| [no-this-expressions](docs/rules/no-this-expressions.md) | Disallow this access. | 🔒 ![badge-noOtherParadigms][] | | ☑️ ✅ | | | | |
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### No Statements
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‎docs/rules/no-class-inheritance.md

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<!-- markdownlint-disable -->
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<!-- begin auto-generated rule header -->
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# Disallow inheritance in classes (`functional/no-class-inheritance`)
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💼 This rule is enabled in the following configs: ☑️ `lite`, `noOtherParadigms`, ✅ `recommended`, 🔒 `strict`.
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<!-- end auto-generated rule header -->
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<!-- markdownlint-restore -->
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<!-- markdownlint-restore -->
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Disallow use of inheritance for classes.
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## Rule Details
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### ❌ Incorrect
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<!-- eslint-skip -->
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```js
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/* eslint functional/no-class-inheritance: "error" */
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abstract class Animal {
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constructor(name, age) {
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this.name = name;
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this.age = age;
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}
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}
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class Dog extends Animal {
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constructor(name, age) {
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super(name, age);
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}
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get ageInDogYears() {
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return 7 * this.age;
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}
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}
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const dogA = new Dog("Jasper", 2);
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console.log(`${dogA.name} is ${dogA.ageInDogYears} in dog years.`);
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```
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### ✅ Correct
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```js
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/* eslint functional/no-class-inheritance: "error" */
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class Animal {
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constructor(name, age) {
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this.name = name;
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this.age = age;
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}
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}
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class Dog {
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constructor(name, age) {
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this.animal = new Animal(name, age);
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}
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get ageInDogYears() {
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return 7 * this.animal.age;
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}
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}
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console.log(`${dogA.name} is ${getAgeInDogYears(dogA.age)} in dog years.`);
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```
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## Options
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This rule accepts an options object of the following type:
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```ts
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type Options = {
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ignoreIdentifierPattern?: string[] | string;
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ignoreCodePattern?: string[] | string;
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};
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```
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### Default Options
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```ts
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const defaults = {};
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```
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### `ignoreIdentifierPattern`
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This option takes a RegExp string or an array of RegExp strings.
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It allows for the ability to ignore violations based on the class's name.
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### `ignoreCodePattern`
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This option takes a RegExp string or an array of RegExp strings.
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It allows for the ability to ignore violations based on the code itself.

‎docs/rules/no-classes.md

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# Disallow classes (`functional/no-classes`)
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💼 This rule is enabled in the following configs: ☑️ `lite`, `noOtherParadigms`, ✅ `recommended`, 🔒 `strict`.
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💼🚫 This rule is enabled in the following configs: `noOtherParadigms`, ✅ `recommended`, 🔒 `strict`. This rule is _disabled_ in the ☑️ `lite` config.
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<!-- end auto-generated rule header -->
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<!-- markdownlint-restore -->

‎eslint.config.js

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@@ -130,6 +130,8 @@ const configs = await rsEslint(
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embeddedLanguageFormatting: "off",
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},
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],
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"max-classes-per-file": "off",
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"ts/no-extraneous-class": "off",
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},
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},
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);

‎src/configs/lite.ts

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@@ -2,6 +2,7 @@ import type { FlatConfig } from "@typescript-eslint/utils/ts-eslint";
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import * as functionalParameters from "#/rules/functional-parameters";
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import * as immutableData from "#/rules/immutable-data";
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import * as noClasses from "#/rules/no-classes";
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import * as noConditionalStatements from "#/rules/no-conditional-statements";
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import * as noExpressionStatements from "#/rules/no-expression-statements";
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import * as preferImmutableTypes from "#/rules/prefer-immutable-types";
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},
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],
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[immutableData.fullName]: ["error", { ignoreClasses: "fieldsOnly" }],
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[noClasses.fullName]: "off",
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[noConditionalStatements.fullName]: "off",
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[noExpressionStatements.fullName]: "off",
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[preferImmutableTypes.fullName]: [

‎src/rules/index.ts

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import * as functionalParameters from "./functional-parameters";
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import * as immutableData from "./immutable-data";
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import * as noClassInheritance from "./no-class-inheritance";
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import * as noClasses from "./no-classes";
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import * as noConditionalStatements from "./no-conditional-statements";
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import * as noExpressionStatements from "./no-expression-statements";
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[functionalParameters.name]: typeof functionalParameters.rule;
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[immutableData.name]: typeof immutableData.rule;
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[noClasses.name]: typeof noClasses.rule;
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[noClassInheritance.name]: typeof noClassInheritance.rule;
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[noConditionalStatements.name]: typeof noConditionalStatements.rule;
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[noExpressionStatements.name]: typeof noExpressionStatements.rule;
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[noLet.name]: typeof noLet.rule;
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[functionalParameters.name]: functionalParameters.rule,
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[immutableData.name]: immutableData.rule,
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[noClasses.name]: noClasses.rule,
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[noClassInheritance.name]: noClassInheritance.rule,
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[noConditionalStatements.name]: noConditionalStatements.rule,
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[noExpressionStatements.name]: noExpressionStatements.rule,
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[noLet.name]: noLet.rule,

‎src/rules/no-class-inheritance.ts

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import type { JSONSchema4 } from "@typescript-eslint/utils/json-schema";
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import type { RuleContext } from "@typescript-eslint/utils/ts-eslint";
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import { deepmerge } from "deepmerge-ts";
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import {
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type IgnoreCodePatternOption,
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type IgnoreIdentifierPatternOption,
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ignoreCodePatternOptionSchema,
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ignoreIdentifierPatternOptionSchema,
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shouldIgnorePattern,
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} from "#/options";
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import { ruleNameScope } from "#/utils/misc";
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import type { ESClass } from "#/utils/node-types";
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import { type NamedCreateRuleCustomMeta, type Rule, type RuleResult, createRule } from "#/utils/rule";
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/**
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* The name of this rule.
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*/
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export const name = "no-class-inheritance";
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/**
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* The full name of this rule.
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*/
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export const fullName: `${typeof ruleNameScope}/${typeof name}` = `${ruleNameScope}/${name}`;
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/**
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* The options this rule can take.
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*/
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type Options = [IgnoreIdentifierPatternOption & IgnoreCodePatternOption];
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/**
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* The schema for the rule options.
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*/
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const schema: JSONSchema4[] = [
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{
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type: "object",
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properties: deepmerge(ignoreIdentifierPatternOptionSchema, ignoreCodePatternOptionSchema),
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additionalProperties: false,
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},
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];
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/**
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* The default options for the rule.
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*/
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const defaultOptions: Options = [{}];
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/**
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* The possible error messages.
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*/
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const errorMessages = {
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abstract: "Unexpected abstract class.",
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extends: "Unexpected inheritance, use composition instead.",
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} as const;
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/**
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* The meta data for this rule.
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*/
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const meta: NamedCreateRuleCustomMeta<keyof typeof errorMessages> = {
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type: "suggestion",
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docs: {
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category: "No Other Paradigms",
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description: "Disallow inheritance in classes.",
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recommended: "recommended",
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recommendedSeverity: "error",
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requiresTypeChecking: false,
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},
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messages: errorMessages,
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schema,
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};
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/**
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* Check if the given class node violates this rule.
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*/
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function checkClass(
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node: ESClass,
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context: Readonly<RuleContext<keyof typeof errorMessages, Options>>,
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options: Readonly<Options>,
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): RuleResult<keyof typeof errorMessages, Options> {
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const [optionsObject] = options;
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const { ignoreIdentifierPattern, ignoreCodePattern } = optionsObject;
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const mut_descriptors: Array<RuleResult<keyof typeof errorMessages, Options>["descriptors"][number]> = [];
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if (!shouldIgnorePattern(node, context, ignoreIdentifierPattern, undefined, ignoreCodePattern)) {
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if (node.abstract) {
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const nodeText = context.sourceCode.getText(node);
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const abstractRelativeIndex = nodeText.indexOf("abstract");
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const abstractIndex = context.sourceCode.getIndexFromLoc(node.loc.start) + abstractRelativeIndex;
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const start = context.sourceCode.getLocFromIndex(abstractIndex);
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const end = context.sourceCode.getLocFromIndex(abstractIndex + "abstract".length);
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mut_descriptors.push({
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node,
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loc: {
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start,
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end,
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},
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messageId: "abstract",
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});
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}
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if (node.superClass !== null) {
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const nodeText = context.sourceCode.getText(node);
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const extendsRelativeIndex = nodeText.indexOf("extends");
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const extendsIndex = context.sourceCode.getIndexFromLoc(node.loc.start) + extendsRelativeIndex;
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const start = context.sourceCode.getLocFromIndex(extendsIndex);
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const { end } = node.superClass.loc;
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mut_descriptors.push({
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node,
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loc: {
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start,
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end,
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},
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messageId: "extends",
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});
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}
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}
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return {
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context,
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descriptors: mut_descriptors,
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};
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}
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// Create the rule.
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export const rule: Rule<keyof typeof errorMessages, Options> = createRule<keyof typeof errorMessages, Options>(
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name,
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meta,
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defaultOptions,
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{
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ClassDeclaration: checkClass,
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ClassExpression: checkClass,
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},
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);

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