npm package: @stdlib/ndarray-base-buffer-dtype-enum
Description: Return the data type enumeration constant of an ndarray data buffer.
Author: The Stdlib Authors
Latest version: 0.3.1

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# Buffer Data Type Enumeration Constant

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> Return the data type enumeration constant of an ndarray data buffer.

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/ndarray-base-buffer-dtype-enum
```

</section>

<section class="usage">

## Usage

```javascript
var dtypeEnum = require( '@stdlib/ndarray-base-buffer-dtype-enum' );
```

#### dtypeEnum( buffer )

Returns the [data type][@stdlib/ndarray/dtypes] enumeration constant of an ndarray data [buffer][@stdlib/ndarray/base/buffer-ctors].

```javascript
var Float64Array = require( '@stdlib/array-float64' );
var buf = new Float64Array( 10 );

var c = dtypeEnum( buf );
// returns <number>
```

If provided an ndarray data [buffer][@stdlib/ndarray/base/buffer-ctors] having an unknown or unsupported [data type][@stdlib/ndarray/dtypes], the function returns `null`.

```javascript
var c = dtypeEnum( 'beep' );
// returns null
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

-   The principle use case for this function is JavaScript-C interoperability. In C, dtypes are assigned integer enumeration constants, not string values.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var dtypes = require( '@stdlib/ndarray-dtypes' );
var bufferCtors = require( '@stdlib/ndarray-base-buffer-ctors' );
var dtypeEnum = require( '@stdlib/ndarray-base-buffer-dtype-enum' );

// Get a list of supported ndarray buffer data types:
var DTYPES = dtypes( 'integer_and_generic' );

// Buffer length:
var len = 10;

// For each supported data type, create a buffer and retrieve its data type enumeration constant...
var ctor;
var i;
for ( i = 0; i < DTYPES.length; i++ ) {
    ctor = bufferCtors( DTYPES[ i ] );
    console.log( '%s => %d', DTYPES[ i ], dtypeEnum( new ctor( len ) ) );
}

// Try an array-like object...
var buf = {
    'length': len
};
console.log( '%s => %s', 'generic', dtypeEnum( buf ) );
```

</section>

<!-- /.examples -->

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* * *

## Notice

This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].

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---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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[@stdlib/ndarray/dtypes]: https://www.npmjs.com/package/@stdlib/ndarray-dtypes

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