79 lines
1.9 KiB
Plaintext
79 lines
1.9 KiB
Plaintext
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---
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description: 'Require `Array#sort` and `Array#toSorted` calls to always provide a `compareFunction`.'
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---
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> 🛑 This file is source code, not the primary documentation location! 🛑
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>
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> See **https://typescript-eslint.io/rules/require-array-sort-compare** for documentation.
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When called without a compare function, `Array#sort()` and `Array#toSorted()` converts all non-undefined array elements into strings and then compares said strings based off their UTF-16 code units [[ECMA specification](https://www.ecma-international.org/ecma-262/9.0/#sec-sortcompare)].
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The result is that elements are sorted alphabetically, regardless of their type.
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For example, when sorting numbers, this results in a "10 before 2" order:
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```ts
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[1, 2, 3, 10, 20, 30].sort(); //→ [1, 10, 2, 20, 3, 30]
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```
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This rule reports on any call to the sort methods that do not provide a `compare` argument.
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## Examples
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This rule aims to ensure all calls of the native sort methods provide a `compareFunction`, while ignoring calls to user-defined methods.
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<!--tabs-->
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### ❌ Incorrect
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```ts
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const array: any[];
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const stringArray: string[];
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array.sort();
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// String arrays should be sorted using `String#localeCompare`.
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stringArray.sort();
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```
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### ✅ Correct
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```ts
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const array: any[];
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const userDefinedType: { sort(): void };
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array.sort((a, b) => a - b);
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array.sort((a, b) => a.localeCompare(b));
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userDefinedType.sort();
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```
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## Options
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### `ignoreStringArrays`
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Examples of code for this rule with `{ ignoreStringArrays: true }`:
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<!--tabs-->
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#### ❌ Incorrect
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```ts option='{ "ignoreStringArrays": true }'
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const one = 1;
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const two = 2;
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const three = 3;
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[one, two, three].sort();
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```
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#### ✅ Correct
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```ts option='{ "ignoreStringArrays": true }'
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const one = '1';
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const two = '2';
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const three = '3';
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[one, two, three].sort();
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```
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## When Not To Use It
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If you intentionally want your arrays to be always sorted in a string-like manner, you can turn this rule off safely.
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