mirror of
https://github.com/Sevichecc/Urara-Blog.git
synced 2025-05-04 17:29:31 +08:00
92 lines
2.3 KiB
Text
92 lines
2.3 KiB
Text
---
|
|
description: 'Enforce `includes` method over `indexOf` method.'
|
|
---
|
|
|
|
> 🛑 This file is source code, not the primary documentation location! 🛑
|
|
>
|
|
> See **https://typescript-eslint.io/rules/prefer-includes** for documentation.
|
|
|
|
Until ES5, we were using `String#indexOf` method to check whether a string contains an arbitrary substring or not.
|
|
Until ES2015, we were using `Array#indexOf` method to check whether an array contains an arbitrary value or not.
|
|
|
|
ES2015 has added `String#includes` and ES2016 has added `Array#includes`.
|
|
It makes code more understandable if we use those `includes` methods for the purpose.
|
|
|
|
## Rule Details
|
|
|
|
This rule is aimed at suggesting `includes` method if `indexOf` method was used to check whether an object contains an arbitrary value or not.
|
|
|
|
If the receiver object of the `indexOf` method call has `includes` method and the two methods have the same parameters, this rule does suggestion.
|
|
There are such types: `String`, `Array`, `ReadonlyArray`, and typed arrays.
|
|
|
|
Additionally, this rule reports the tests of simple regular expressions in favor of `String#includes`.
|
|
|
|
Examples of code for this rule:
|
|
|
|
<!--tabs-->
|
|
|
|
### ❌ Incorrect
|
|
|
|
```ts
|
|
let str: string;
|
|
let array: any[];
|
|
let readonlyArray: ReadonlyArray<any>;
|
|
let typedArray: UInt8Array;
|
|
let maybe: string;
|
|
let userDefined: {
|
|
indexOf(x: any): number;
|
|
includes(x: any): boolean;
|
|
};
|
|
|
|
str.indexOf(value) !== -1;
|
|
array.indexOf(value) !== -1;
|
|
readonlyArray.indexOf(value) === -1;
|
|
typedArray.indexOf(value) > -1;
|
|
maybe?.indexOf('') !== -1;
|
|
userDefined.indexOf(value) >= 0;
|
|
|
|
// simple RegExp test
|
|
/foo/.test(str);
|
|
```
|
|
|
|
### ✅ Correct
|
|
|
|
```ts
|
|
let array: any[];
|
|
let readonlyArray: ReadonlyArray<any>;
|
|
let typedArray: UInt8Array;
|
|
let userDefined: {
|
|
indexOf(x: any): number;
|
|
includes(x: any): boolean;
|
|
};
|
|
let mismatchExample: {
|
|
indexOf(x: any, fromIndex?: number): number;
|
|
includes(x: any): boolean;
|
|
};
|
|
|
|
str.includes(value);
|
|
array.includes(value);
|
|
readonlyArray.includes(value);
|
|
typedArray.includes(value);
|
|
userDefined.includes(value);
|
|
|
|
// the two methods have different parameters.
|
|
mismatchExample.indexOf(value) >= 0;
|
|
```
|
|
|
|
## Options
|
|
|
|
```jsonc
|
|
// .eslintrc.json
|
|
{
|
|
"rules": {
|
|
"@typescript-eslint/prefer-includes": "warn"
|
|
}
|
|
}
|
|
```
|
|
|
|
This rule is not configurable.
|
|
|
|
## When Not To Use It
|
|
|
|
If you don't want to suggest `includes`, you can safely turn this rule off.
|