npm package: @stdlib/wasm-memory
Description: WebAssembly memory.
Author: The Stdlib Authors
Latest version: 0.1.1

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<details>
  <summary>
    About stdlib...
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</details>

# Memory

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> WebAssembly [memory][mdn-webassembly-memory] constructor.

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/wasm-memory
```

</section>

<section class="usage">

## Usage

```javascript
var Memory = require( '@stdlib/wasm-memory' );
```

#### Memory( descriptor )

Returns a new WebAssembly [memory][mdn-webassembly-memory] instance.

```javascript
var mem = new Memory({
    'initial': 0
});
// returns <Memory>
```

The `descriptor` argument is an object which supports the following properties:

-   **initial**: (_required_) initial memory size in units of WebAssembly pages (i.e., 64KiB).
-   **maximum**: maximum memory size in units of WebAssembly pages (i.e., 64KiB).
-   **shared**: boolean indicating whether the memory is shared. Default: `false`.

* * *

<a name="prop-buffer"></a>

#### Memory.prototype.buffer

**Read-only** property which returns the [`ArrayBuffer`][@stdlib/array/buffer] (or [`SharedArrayBuffer`][@stdlib/array/shared-buffer]) referenced by memory instance.

```javascript
var mem = new Memory({
    'initial': 0
});

var buf = mem.buffer;
// returns <ArrayBuffer>
```

* * *

### Methods

<a name="method-grow"></a>

#### Memory.prototype.grow( delta )

Increases the size of the memory instance by a specified number of WebAssembly pages (i.e., 64KiB).

```javascript
var mem = new Memory({
    'initial': 0
});

// ...

var prevSize = mem.grow( 1 );
```

The method returns the size of the previous [`ArrayBuffer`][@stdlib/array/buffer] (or [`SharedArrayBuffer`][@stdlib/array/shared-buffer]).

</section>

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* * *

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

<section class="notes">

## Notes

-   Upon increasing the size, the previous [`ArrayBuffer`][@stdlib/array/buffer] is detached, thus invalidating any typed arrays which were views over the previous [`ArrayBuffer`][@stdlib/array/buffer].
-   **Detachment** means that the previous [`ArrayBuffer`][@stdlib/array/buffer] byte length becomes zero, and it no longer has bytes accessible to JavaScript.
-   When calling `grow`, [`ArrayBuffer`][@stdlib/array/buffer] detachment applies even when `delta` is zero.
-   Detachment only applies for non-shared memory instances. For a shared memory instance, the initial buffer (which is a [`SharedArrayBuffer`][@stdlib/array/shared-buffer]) will not become detached and, instead, its length will not be updated.
-   Accesses to the `buffer` property after growing a [`SharedArrayBuffer`][@stdlib/array/shared-buffer] will yield a larger [`SharedArrayBuffer`][@stdlib/array/shared-buffer] which may access a larger span of memory than the buffer before growing memory.
-   Every [`SharedArrayBuffer`][@stdlib/array/shared-buffer] accessed via the `buffer` property will always refer to the start of the same memory address range and thus manipulate the same data.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var hasWebAssemblySupport = require( '@stdlib/assert-has-wasm-support' );
var DataView = require( '@stdlib/array-dataview' );
var Memory = require( '@stdlib/wasm-memory' );

function main() {
    var view;
    var mem;
    var v;
    if ( !hasWebAssemblySupport() ) {
        console.error( 'Environment does not support WebAssembly.' );
        return;
    }
    mem = new Memory({
        'initial': 1
    });
    view = new DataView( mem.buffer );

    view.setFloat64( 0, 3.14 );

    // ...

    v = view.getFloat64( 0 );
    console.log( v );
    // => 3.14
}

main();
```

</section>

<!-- /.examples -->

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</section>

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</section>

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<section class="main-repo" >

* * *

## 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].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

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

</section>

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[npm-image]: http://img.shields.io/npm/v/@stdlib/wasm-memory.svg
[npm-url]: https://npmjs.org/package/@stdlib/wasm-memory

[test-image]: https://github.com/stdlib-js/wasm-memory/actions/workflows/test.yml/badge.svg?branch=v0.1.1
[test-url]: https://github.com/stdlib-js/wasm-memory/actions/workflows/test.yml?query=branch:v0.1.1

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/wasm-memory/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/wasm-memory?branch=main

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[stdlib]: https://github.com/stdlib-js/stdlib

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[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

[deno-url]: https://github.com/stdlib-js/wasm-memory/tree/deno
[deno-readme]: https://github.com/stdlib-js/wasm-memory/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/wasm-memory/tree/umd
[umd-readme]: https://github.com/stdlib-js/wasm-memory/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/wasm-memory/tree/esm
[esm-readme]: https://github.com/stdlib-js/wasm-memory/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/wasm-memory/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/wasm-memory/main/LICENSE

[mdn-webassembly-memory]: https://developer.mozilla.org/en-US/docs/WebAssembly/JavaScript_interface/Memory

[@stdlib/array/buffer]: https://www.npmjs.com/package/@stdlib/array-buffer

[@stdlib/array/shared-buffer]: https://www.npmjs.com/package/@stdlib/array-shared-buffer

</section>

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