> For AI agents: the complete documentation index is available at https://rslint.rs/llms.txt, the full documentation bundle is available at https://rslint.rs/llms-full.txt.

# prefer-string-trim-start-end

[Added in v0.9.2](https://github.com/web-infra-dev/rslint/releases/tag/v0.9.2)
## Configuration

| Preset                              | Configured Value |
| ----------------------------------- | ---------------- |
| ✅ unicornPlugin.configs.recommended | `"error"`        |


```ts title=rslint.config.ts
import { defineConfig, unicornPlugin } from '@rslint/core';

export default defineConfig([
  unicornPlugin.configs.recommended,
  {
    rules: {
      'unicorn/prefer-string-trim-start-end': 'error',
    },
  },
]);
```

## Rule Details

Prefer `String#trimStart()` and `String#trimEnd()` over the legacy
`String#trimLeft()` and `String#trimRight()` aliases. The preferred names are
direction-independent and therefore clearer for both left-to-right and
right-to-left text.

Examples of **incorrect** code for this rule:

```javascript
const leading = value.trimLeft();
const trailing = value.trimRight();
```

Examples of **correct** code for this rule:

```javascript
const leading = value.trimStart();
const trailing = value.trimEnd();
```

Optional access is checked, while an optional call is left unchanged:

```javascript
value?.trimLeft(); // Reported and fixed to value?.trimStart()
value.trimLeft?.(); // Allowed
```

## Original Documentation

- [eslint-plugin-unicorn: prefer-string-trim-start-end](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/v74.0.0/docs/rules/prefer-string-trim-start-end.md)
- [Source code](https://github.com/sindresorhus/eslint-plugin-unicorn/blob/v74.0.0/rules/prefer-string-trim-start-end.js)