time-to-botec/squiggle/node_modules/@stdlib/string/code-point-at/README.md

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# codePointAt

> Return a Unicode [code point][code-point] from a string at a specified position.

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## Usage

```javascript
var codePointAt = require( '@stdlib/string/code-point-at' );
```

#### codePointAt( string, position\[, backward] )

Returns a Unicode [code point][code-point] from a string at a specified position.

```javascript
var out = codePointAt( 'last man standing', 4 );
// returns 32
```

The function supports providing a `boolean` argument for performing backward iteration for low surrogates.

```javascript
var out = codePointAt( '🌷', 1, true );
// returns 127799
```

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## Notes

This function differs from [`String.prototype.codePointAt`][mdn-string-codepointat] in the following ways:

-   The function supports providing a `boolean` argument for performing backward iteration for low surrogates. [`String.prototype.codePointAt`][mdn-string-codepointat] simply returns the low surrogate value if no [UTF-16][utf-16] surrogate pair begins at the specified position. If invoked with `backward` set to `true`, this function will return the code point after aggregating with the preceding high surrogate, if the specified position does not mark the start of a surrogate pair.

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## Examples

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```javascript
var codePointAt = require( '@stdlib/string/code-point-at' );

console.log( codePointAt( 'last man standing', 4 ) );
// => 32

console.log( codePointAt( 'presidential election', 8, true ) );
// => 116

console.log( codePointAt( 'अनुच्छेद', 2 ) );
// => 2369

console.log( codePointAt( '🌷', 1, true ) );
// => 127799
```

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* * *

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## CLI

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### Usage

```text
Usage: code-point-at [options] [<string>] --pos=<index>

Options:

  -h,    --help                Print this message.
  -V,    --version             Print the package version.
  -b,    --backward            Backward iteration for low surrogates.
         --pos index           Position in string.
```

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### Examples

```bash
$ code-point-at --pos=2 अनुच्छेद
2369
```

To use as a [standard stream][standard-streams],

```bash
$ echo -n 'अनुच्छेद' | code-point-at --pos=2
2369
```

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* * *

## See Also

-   <span class="package-name">[`@stdlib/string/from-code-point`][@stdlib/string/from-code-point]</span><span class="delimiter">: </span><span class="description">create a string from a sequence of Unicode code points.</span>

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[code-point]: https://en.wikipedia.org/wiki/Code_point

[standard-streams]: https://en.wikipedia.org/wiki/Standard_streams

[mdn-string-codepointat]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/codePointAt

[utf-16]: https://en.wikipedia.org/wiki/UTF-16

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[@stdlib/string/from-code-point]: https://github.com/stdlib-js/string/tree/main/from-code-point

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