feat: added strict equal (#128)

Author: veritem

README.md

@@ -103,6 +103,7 @@ To use the all configuration, extend it in your `.eslintrc` file:
 | [prefer-called-with](docs/rules/prefer-called-with.md)                       | Suggest using `toBeCalledWith()` or `toHaveBeenCalledWith()`             | 🌐 |    |    |
 | [prefer-equality-matcher](docs/rules/prefer-equality-matcher.md)             | Suggest using the built-in quality matchers                              | 🌐 |    | 💡 |
 | [prefer-lowercase-title](docs/rules/prefer-lowercase-title.md)               | Enforce lowercase titles                                                 | 🌐 | 🔧 |    |
+| [prefer-strict-equal](docs/rules/prefer-strict-equal.md)                     | Prefer strict equal over equal                                           | 🌐 |    | 💡 |
 | [prefer-to-be](docs/rules/prefer-to-be.md)                                   | Suggest using toBe()                                                     | ✅  | 🔧 |    |
 | [prefer-to-be-falsy](docs/rules/prefer-to-be-falsy.md)                       | Suggest using toBeFalsy()                                                | 🌐 | 🔧 |    |
 | [prefer-to-be-object](docs/rules/prefer-to-be-object.md)                     | Prefer toBeObject()                                                      | 🌐 | 🔧 |    |

docs/rules/prefer-strict-equal.md

@@ -0,0 +1,17 @@
+# Prefer strict equal over equal (`vitest/prefer-strict-equal`)
+
+⚠️ This rule _warns_ in the 🌐 `all` config.
+
+💡 This rule is manually fixable by [editor suggestions](https://eslint.org/docs/developer-guide/working-with-rules#providing-suggestions).
+
+<!-- end auto-generated rule header -->
+
+```ts
+// bad
+
+expect(something).toEqual(somethingElse);
+
+// good
+expect(something).toStrictEqual(somethingElse);
+
+```

src/index.ts

@@ -32,6 +32,7 @@ import preferToBeTruthy, { RULE_NAME as preferToBeTruthyName } from './rules/pre
 import preferToBeFalsy, { RULE_NAME as preferToBeFalsyName } from './rules/prefer-to-be-falsy'
 import preferToHaveLength, { RULE_NAME as preferToHaveLengthName } from './rules/prefer-to-have-length'
 import preferEqualityMatcher, { RULE_NAME as preferEqualityMatcherName } from './rules/prefer-equality-matcher'
+import preferStrictEqual, { RULE_NAME as preferStrictEqualName } from './rules/prefer-strict-equal'
 
 const createConfig = (rules: Record<string, string>) => ({
 	plugins: ['vitest'],
@@ -71,7 +72,8 @@ const allRules = {
 	[preferToBeObjectName]: 'warn',
 	[preferToBeTruthyName]: 'warn',
 	[preferToHaveLengthName]: 'warn',
-	[preferEqualityMatcherName]: 'warn'
+	[preferEqualityMatcherName]: 'warn',
+	[preferStrictEqualName]: 'warn'
 }
 
 const recommended = {
@@ -118,7 +120,8 @@ export default {
 		[preferToBeObjectName]: preferToBeObject,
 		[preferToBeTruthyName]: preferToBeTruthy,
 		[preferToHaveLengthName]: preferToHaveLength,
-		[preferEqualityMatcherName]: preferEqualityMatcher
+		[preferEqualityMatcherName]: preferEqualityMatcher,
+		[preferStrictEqualName]: preferStrictEqual
 	},
 	configs: {
 		all: createConfig(allRules),

src/rules/prefer-strict-equal.test.ts

@@ -0,0 +1,66 @@
+import { describe, it } from 'vitest'
+import ruleTester from '../utils/tester'
+import rule, { RULE_NAME } from './prefer-strict-equal'
+
+describe(RULE_NAME, () => {
+	it(RULE_NAME, () => {
+		ruleTester.run(RULE_NAME, rule, {
+			valid: [
+				'expect(something).toStrictEqual(somethingElse);',
+				'a().toEqual(\'b\')',
+				'expect(a);'
+			],
+			invalid: [
+				{
+					code: 'expect(something).toEqual(somethingElse);',
+					errors: [
+						{
+							messageId: 'useToStrictEqual',
+							column: 19,
+							line: 1,
+							suggestions: [
+								{
+									messageId: 'suggestReplaceWithStrictEqual',
+									output: 'expect(something).toStrictEqual(somethingElse);'
+								}
+							]
+						}
+					]
+				},
+				{
+					code: 'expect(something).toEqual(somethingElse,);',
+					parserOptions: { ecmaVersion: 2017 },
+					errors: [
+						{
+							messageId: 'useToStrictEqual',
+							column: 19,
+							line: 1,
+							suggestions: [
+								{
+									messageId: 'suggestReplaceWithStrictEqual',
+									output: 'expect(something).toStrictEqual(somethingElse,);'
+								}
+							]
+						}
+					]
+				},
+				{
+					code: 'expect(something)["toEqual"](somethingElse);',
+					errors: [
+						{
+							messageId: 'useToStrictEqual',
+							column: 19,
+							line: 1,
+							suggestions: [
+								{
+									messageId: 'suggestReplaceWithStrictEqual',
+									output: 'expect(something)[\'toStrictEqual\'](somethingElse);'
+								}
+							]
+						}
+					]
+				}
+			]
+		})
+	})
+})

src/rules/prefer-strict-equal.ts

@@ -0,0 +1,51 @@
+import { createEslintRule, isSupportedAccessor, replaceAccessorFixer } from '../utils'
+import { parseVitestFnCall } from '../utils/parseVitestFnCall'
+import { EqualityMatcher } from '../utils/types'
+
+export const RULE_NAME = 'prefer-strict-equal'
+export type MESSAGE_IDS = 'useToStrictEqual' | 'suggestReplaceWithStrictEqual'
+type Options = []
+
+export default createEslintRule<Options, MESSAGE_IDS>({
+	name: RULE_NAME,
+	meta: {
+		type: 'suggestion',
+		docs: {
+			description: 'Prefer strict equal over equal',
+			recommended: 'warn'
+		},
+		messages: {
+			useToStrictEqual: 'Use `toStrictEqual()` instead',
+			suggestReplaceWithStrictEqual: 'Replace with `toStrictEqual()`'
+		},
+		schema: [],
+		hasSuggestions: true
+	},
+	defaultOptions: [],
+	create(context) {
+		return {
+			CallExpression(node) {
+				const vitestFnCall = parseVitestFnCall(node, context)
+
+				if (vitestFnCall?.type !== 'expect') return
+
+				const { matcher } = vitestFnCall
+
+				if (isSupportedAccessor(matcher, 'toEqual')) {
+					context.report({
+						messageId: 'useToStrictEqual',
+						node: matcher,
+						suggest: [
+							{
+								messageId: 'suggestReplaceWithStrictEqual',
+								fix: fixer => [
+									replaceAccessorFixer(fixer, matcher, EqualityMatcher.toStrictEqual)
+								]
+							}
+						]
+					})
+				}
+			}
+		}
+	}
+})