string-match-left-right/README.md

Match substrings on the left or right of a given index, ignoring whitespace

<h1 align="center">string-match-left-right</h1>

<p align="center">Match substrings on the left or right of a given index, ignoring whitespace</p>

<p align="center">
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## Install

This package is [pure ESM](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c). If you're not ready yet, install an older version of this program, 7.1.0 (`npm i string-match-left-right@7.1.0`).

```bash
npm i string-match-left-right
```

## Quick Take

```js
import { strict as assert } from "assert";

import {
  matchLeftIncl,
  matchRightIncl,
  matchLeft,
  matchRight,
} from "string-match-left-right";

// 3rd character is "d" because indexes start from zero.
// We're checking the string to the left of it, "bcd", inclusive of current character ("d").
// This means, "bcd" has to end with existing character and the other chars to the left
// must match exactly:
assert.equal(matchLeftIncl("abcdefghi", 3, ["bcd"]), "bcd");

// neither "ab" nor "zz" are to the left of 3rd index, "d":
assert.equal(matchLeft("abcdefghi", 3, ["ab", "zz"]), false);

// "def" is to the right of 3rd index (including it), "d":
assert.equal(matchRightIncl("abcdefghi", 3, ["def", "zzz"]), "def");

// One of values, "ef" is exactly to the right of 3rd index, "d":
assert.equal(matchRight("abcdefghi", 3, ["ef", "zz"]), "ef");
```

## Documentation

Please [visit codsen.com](https://codsen.com/os/string-match-left-right/) for a full description of the API.

## Contributing

To report bugs or request features or assistance, [raise an issue](https://github.com/codsen/codsen/issues/new/choose) on GitHub.

## Licence

MIT License.

Copyright © 2010-2025 Roy Revelt and other contributors.

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