npm package: @stdlib/array-filled-by
Description: Create a filled array according to a provided callback function.
Author: The Stdlib Authors
Latest version: 0.3.1

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# filledarrayBy

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

> Create a filled array according to a provided callback function.

<!-- 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>

<!-- /.intro -->

<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/array-filled-by
```

</section>

<section class="usage">

## Usage

```javascript
var filledarrayBy = require( '@stdlib/array-filled-by' );
```

#### filledarrayBy( \[dtype] )

Creates a filled array having a specified [data type][@stdlib/array/dtypes] `dtype`.

```javascript
var arr = filledarrayBy();
// returns <Float64Array>
```

By default, the output array [data type][@stdlib/array/dtypes] is `float64` (i.e., a [typed array][mdn-typed-array]). To specify an alternative [data type][@stdlib/array/dtypes], provide a `dtype` argument.

```javascript
var arr = filledarrayBy( 'int32' );
// returns <Int32Array>
```

#### filledarrayBy( length\[, dtype], clbk\[, thisArg] )

Returns a filled array according to a provided callback function and having a specified `length`.

```javascript
function constant() {
    return 1.0;
}

var arr1 = filledarrayBy( 5, constant );
// returns <Float64Array>[ 1.0, 1.0, 1.0, 1.0, 1.0 ]

var arr2 = filledarrayBy( 5, 'uint8', constant );
// returns <Uint8Array>[ 1, 1, 1, 1, 1 ]
```

#### filledarrayBy( array\[, dtype], clbk\[, thisArg] )

Creates a filled array from another array (or array-like object) according to a provided callback function.

```javascript
var arr0 = {
    '0': 0.5,
    '1': 0.5,
    '2': 0.5,
    'length': 3
};

function clbk1() {
    return 1.0;
}
var arr1 = filledarrayBy( arr0, clbk1 );
// returns <Float64Array>[ 1.0, 1.0, 1.0 ]

function clbk2() {
    return 2.0;
}
var arr2 = filledarrayBy( arr1, clbk2 );
// returns <Float64Array>[ 2.0, 2.0, 2.0 ]

function clbk3() {
    return 3.0;
}
var arr3 = filledarrayBy( arr1, 'int32', clbk3 );
// returns <Int32Array>[ 3, 3, 3 ]
```

#### filledarrayBy( iterable\[, dtype], clbk\[, thisArg] )

Creates a filled array from an iterable according to a provided callback function.

```javascript
var iterConstant = require( '@stdlib/iter-constant' );

function clbk() {
    return 1.0;
}

var it = iterConstant( 3.0, {
    'iter': 3
});

var arr1 = filledarrayBy( it, clbk );
// returns <Float64Array>[ 1.0, 1.0, 1.0 ]

var arr2 = filledarrayBy( it, 'float32', clbk );
// returns <Float32Array>[ 1.0, 1.0, 1.0 ]
```

#### filledarrayBy( buffer\[, byteOffset\[, length]]\[, dtype], clbk\[, thisArg] )

Returns a filled [typed array][mdn-typed-array] view of an [`ArrayBuffer`][mdn-arraybuffer] according to a provided callback function.

```javascript
var ArrayBuffer = require( '@stdlib/array-buffer' );

function clbk() {
    return 1.0;
}

var buf = new ArrayBuffer( 32 );
var arr = filledarrayBy( buf, clbk );
// returns <Float64Array>[ 1.0, 1.0, 1.0, 1.0 ]

buf = new ArrayBuffer( 32 );
arr = filledarrayBy( buf, 'float32', clbk );
// returns <Float32Array>[ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ]

buf = new ArrayBuffer( 32 );
arr = filledarrayBy( buf, 16, clbk );
// returns <Float64Array>[ 1.0, 1.0 ]

buf = new ArrayBuffer( 32 );
arr = filledarrayBy( buf, 16, 'float32', clbk );
// returns <Float32Array>[ 1.0, 1.0, 1.0, 1.0 ]

buf = new ArrayBuffer( 32 );
arr = filledarrayBy( buf, 16, 1, clbk );
// returns <Float64Array>[ 1.0 ]

buf = new ArrayBuffer( 32 );
arr = filledarrayBy( buf, 10, 4, 'int16', clbk );
// returns <Int16Array>[ 1, 1, 1, 1 ]
```

</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

-   Creating a generic [array][mdn-array] from an [`ArrayBuffer`][mdn-arraybuffer] is **not** supported.

-   A callback function is provided a single argument:

    -   **index**: the current array index.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' ).factory;
var dtypes = require( '@stdlib/array-typed-real-dtypes' );
var filledarrayBy = require( '@stdlib/array-filled-by' );

// Create a pseudorandom number generator:
var rand = discreteUniform( 0, 100 );

// Get a list of array data types:
var dt = dtypes();

// Generate filled arrays...
var arr;
var i;
for ( i = 0; i < dt.length; i++ ) {
    arr = filledarrayBy( 10, dt[ i ], rand );
    console.log( arr );
}
```

</section>

<!-- /.examples -->

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<section class="references">

</section>

<!-- /.references -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/array-filled`][@stdlib/array/filled]</span><span class="delimiter">: </span><span class="description">create a filled array.</span>
-   <span class="package-name">[`@stdlib/array-typed`][@stdlib/array/typed]</span><span class="delimiter">: </span><span class="description">create a typed array.</span>

</section>

<!-- /.related -->

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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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[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/array-filled-by/tree/deno
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/array-filled-by/main/LICENSE

[mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array

[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray

[mdn-arraybuffer]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer

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

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

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

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