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katakonstSimenB
katakonst
authored and
SimenB
committedOct 14, 2018
feat: add prefer-to-contain rule (#174)
Fixes #100
·
v28.11.0v21.25.0
1 parent 9466959 commit 83a4c48

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Diff for: ‎README.md

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Original file line numberDiff line numberDiff line change
@@ -97,6 +97,7 @@ for more information about extending configuration files.
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| [prefer-strict-equal][] | Suggest using `toStrictEqual()` | | ![fixable-green][] |
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| [prefer-to-be-null][] | Suggest using `toBeNull()` | | ![fixable-green][] |
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| [prefer-to-be-undefined][] | Suggest using `toBeUndefined()` | | ![fixable-green][] |
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| [prefer-to-contain][] | Suggest using `toContain()` | | ![fixable-green][] |
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| [prefer-to-have-length][] | Suggest using `toHaveLength()` | ![recommended][] | ![fixable-green][] |
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| [prefer-inline-snapshots][] | Suggest using `toMatchInlineSnapshot()` | | ![fixable-green][] |
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| [require-tothrow-message][] | Require that `toThrow()` and `toThrowError` includes a message | | |
@@ -126,6 +127,7 @@ for more information about extending configuration files.
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[prefer-strict-equal]: docs/rules/prefer-strict-equal.md
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[prefer-to-be-null]: docs/rules/prefer-to-be-null.md
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[prefer-to-be-undefined]: docs/rules/prefer-to-be-undefined.md
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[prefer-to-contain]: docs/rules/prefer-to-contain.md
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[prefer-to-have-length]: docs/rules/prefer-to-have-length.md
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[prefer-inline-snapshots]: docs/rules/prefer-inline-snapshots.md
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[require-tothrow-message]: docs/rules/require-tothrow-message.md

Diff for: ‎docs/rules/prefer-to-contain.md

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@@ -0,0 +1,47 @@
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# Suggest using `toContain()` (prefer-to-contain)
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In order to have a better failure message, `toContain()` should be used upon
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asserting expectations on an array containing an object.
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## Rule details
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This rule triggers a warning if `toBe()` or `isEqual()` is used to assert object
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inclusion in an array
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```js
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expect(a.includes(b)).toBe(true);
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```
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```js
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expect(a.includes(b)).not.toBe(true);
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```
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```js
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expect(a.includes(b)).toBe(false);
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```
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### Default configuration
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The following patterns are considered a warning:
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```js
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expect(a.includes(b)).toBe(true);
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```
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```js
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expect(a.includes(b)).not.toBe(true);
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```
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```js
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expect(a.includes(b)).toBe(false);
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```
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The following patterns are not a warning:
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```js
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expect(a).toContain(b);
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```
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```js
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expect(a).not.toContain(b);
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```

Diff for: ‎index.js

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Original file line numberDiff line numberDiff line change
@@ -14,6 +14,7 @@ const noTestPrefixes = require('./rules/no-test-prefixes');
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const noTestReturnStatement = require('./rules/no-test-return-statement');
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const preferToBeNull = require('./rules/prefer-to-be-null');
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const preferToBeUndefined = require('./rules/prefer-to-be-undefined');
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const preferToContain = require('./rules/prefer-to-contain');
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const preferToHaveLength = require('./rules/prefer-to-have-length');
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const validDescribe = require('./rules/valid-describe');
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const validExpect = require('./rules/valid-expect');
@@ -84,6 +85,7 @@ module.exports = {
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'no-test-return-statement': noTestReturnStatement,
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'prefer-to-be-null': preferToBeNull,
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'prefer-to-be-undefined': preferToBeUndefined,
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'prefer-to-contain': preferToContain,
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'prefer-to-have-length': preferToHaveLength,
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'valid-describe': validDescribe,
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'valid-expect': validExpect,

Diff for: ‎rules/__tests__/prefer-to-contain.test.js

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'use strict';
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const RuleTester = require('eslint').RuleTester;
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const rule = require('../prefer-to-contain');
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const ruleTester = new RuleTester();
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ruleTester.run('prefer-to-contain', rule, {
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valid: [
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'expect(a).toContain(b);',
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"expect(a.name).toBe('b');",
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'expect(a).toBe(true);',
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`expect(a).toEqual(b)`,
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`expect(a.test(c)).toEqual(b)`,
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`expect(a.includes(b)).toEqual()`,
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`expect(a.includes(b)).toEqual("test")`,
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`expect(a.includes(b)).toBe("test")`,
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`expect(a.includes()).toEqual()`,
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`expect(a.includes()).toEqual(true)`,
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`expect(a.includes(b,c)).toBe(true)`,
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`expect([{a:1}]).toContain({a:1})`,
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`expect([1].includes(1)).toEqual`,
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`expect([1].includes).toEqual`,
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`expect([1].includes).not`,
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`expect(a.test(b)).resolves.toEqual(true)`,
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`expect(a.test(b)).resolves.not.toEqual(true)`,
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`expect(a).not.toContain(b)`,
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],
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invalid: [
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{
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code: 'expect(a.includes(b)).toEqual(true);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 23,
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line: 1,
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},
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],
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output: 'expect(a).toContain(b);',
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},
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{
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code: 'expect(a.includes(b)).toEqual(false);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 23,
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line: 1,
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},
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],
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output: 'expect(a).not.toContain(b);',
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},
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{
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code: 'expect(a.includes(b)).not.toEqual(false);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 23,
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line: 1,
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},
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],
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output: 'expect(a).toContain(b);',
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},
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{
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code: 'expect(a.includes(b)).not.toEqual(true);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 23,
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line: 1,
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},
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],
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output: 'expect(a).not.toContain(b);',
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},
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{
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code: 'expect(a.includes(b)).toBe(true);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 23,
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line: 1,
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},
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],
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output: 'expect(a).toContain(b);',
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},
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{
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code: 'expect(a.includes(b)).toBe(false);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 23,
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line: 1,
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},
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],
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output: 'expect(a).not.toContain(b);',
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},
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{
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code: 'expect(a.includes(b)).not.toBe(false);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 23,
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line: 1,
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},
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],
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output: 'expect(a).toContain(b);',
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},
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{
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code: 'expect(a.includes(b)).not.toBe(true);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 23,
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line: 1,
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},
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],
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output: 'expect(a).not.toContain(b);',
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},
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{
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code: 'expect(a.test(t).includes(b.test(p))).toEqual(true);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 39,
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line: 1,
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},
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],
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output: 'expect(a.test(t)).toContain(b.test(p));',
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},
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{
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code: 'expect(a.test(t).includes(b.test(p))).toEqual(false);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 39,
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line: 1,
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},
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],
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output: 'expect(a.test(t)).not.toContain(b.test(p));',
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},
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{
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code: 'expect(a.test(t).includes(b.test(p))).not.toEqual(true);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 39,
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line: 1,
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},
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],
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output: 'expect(a.test(t)).not.toContain(b.test(p));',
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},
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{
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code: 'expect(a.test(t).includes(b.test(p))).not.toEqual(false);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 39,
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line: 1,
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},
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],
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output: 'expect(a.test(t)).toContain(b.test(p));',
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},
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{
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code: 'expect([{a:1}].includes({a:1})).toBe(true);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 33,
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line: 1,
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},
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],
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output: 'expect([{a:1}]).toContain({a:1});',
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},
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{
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code: 'expect([{a:1}].includes({a:1})).toBe(false);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 33,
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line: 1,
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},
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],
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output: 'expect([{a:1}]).not.toContain({a:1});',
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},
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{
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code: 'expect([{a:1}].includes({a:1})).not.toBe(true);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 33,
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line: 1,
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},
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],
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output: 'expect([{a:1}]).not.toContain({a:1});',
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},
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{
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code: 'expect([{a:1}].includes({a:1})).not.toBe(false);',
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errors: [
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{
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message: 'Use toContain() instead',
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column: 33,
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line: 1,
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},
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],
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output: 'expect([{a:1}]).toContain({a:1});',
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},
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],
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});

Diff for: ‎rules/prefer-to-contain.js

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1+
'use strict';
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const getDocsUrl = require('./util').getDocsUrl;
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const expectCase = require('./util').expectCase;
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const expectResolveCase = require('./util').expectResolveCase;
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const expectRejectCase = require('./util').expectRejectCase;
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const method = require('./util').method;
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const argument = require('./util').argument;
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const isEqualityCheck = node =>
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method(node) &&
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(method(node).name === 'toBe' || method(node).name === 'toEqual');
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const isArgumentValid = node =>
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argument(node).value === true || argument(node).value === false;
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const hasOneArgument = node => node.arguments && node.arguments.length === 1;
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const isValidEqualityCheck = node =>
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isEqualityCheck(node) &&
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hasOneArgument(node.parent.parent) &&
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isArgumentValid(node);
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const isEqualityNegation = node =>
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method(node).name === 'not' && isValidEqualityCheck(node.parent);
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const hasIncludesMethod = node =>
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node.arguments[0] &&
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node.arguments[0].callee &&
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node.arguments[0].callee.property &&
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node.arguments[0].callee.property.name === 'includes';
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const isValidIncludesMethod = node =>
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hasIncludesMethod(node) && hasOneArgument(node.arguments[0]);
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const getNegationFixes = (node, sourceCode, fixer) => {
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const negationPropertyDot = sourceCode.getFirstTokenBetween(
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node.parent.object,
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node.parent.property,
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token => token.value === '.'
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);
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const toContainFunc =
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isEqualityNegation(node) && argument(node.parent).value
44+
? 'not.toContain'
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: 'toContain';
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//.includes function argument
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const containArg = node.arguments[0].arguments[0];
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return [
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fixer.remove(negationPropertyDot),
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fixer.remove(method(node)),
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fixer.replaceText(method(node.parent), toContainFunc),
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fixer.replaceText(argument(node.parent), sourceCode.getText(containArg)),
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];
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};
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const getCommonFixes = (node, sourceCode, fixer) => {
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const containArg = node.arguments[0].arguments[0];
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const includesCaller = node.arguments[0].callee;
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const propertyDot = sourceCode.getFirstTokenBetween(
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includesCaller.object,
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includesCaller.property,
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token => token.value === '.'
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);
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const closingParenthesis = sourceCode.getTokenAfter(containArg);
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const openParenthesis = sourceCode.getTokenBefore(containArg);
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return [
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fixer.remove(containArg),
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fixer.remove(includesCaller.property),
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fixer.remove(propertyDot),
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fixer.remove(closingParenthesis),
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fixer.remove(openParenthesis),
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];
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};
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module.exports = {
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meta: {
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docs: {
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url: getDocsUrl(__filename),
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},
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fixable: 'code',
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},
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create(context) {
87+
return {
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CallExpression(node) {
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if (
90+
!(expectResolveCase(node) || expectRejectCase(node)) &&
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expectCase(node) &&
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(isEqualityNegation(node) || isValidEqualityCheck(node)) &&
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isValidIncludesMethod(node)
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) {
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context.report({
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fix(fixer) {
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const sourceCode = context.getSourceCode();
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let fixArr = getCommonFixes(node, sourceCode, fixer);
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if (isEqualityNegation(node)) {
101+
return getNegationFixes(node, sourceCode, fixer).concat(fixArr);
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}
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const toContainFunc = argument(node).value
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? 'toContain'
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: 'not.toContain';
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//.includes function argument
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const containArg = node.arguments[0].arguments[0];
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fixArr.push(fixer.replaceText(method(node), toContainFunc));
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fixArr.push(
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fixer.replaceText(
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argument(node),
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sourceCode.getText(containArg)
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)
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);
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return fixArr;
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},
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message: 'Use toContain() instead',
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node: method(node),
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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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