npm package: @stdlib/utils-map-values
Description: Map values from one object to a new object having the same keys.
Author: The Stdlib Authors
Latest version: 0.2.3

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  <summary>
    About stdlib...
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# mapValues

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

> Map values from one object to a new object having the same keys.

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/utils-map-values
```

</section>

<section class="usage">

## Usage

```javascript
var mapValues = require( '@stdlib/utils-map-values' );
```

#### mapValues( obj, transform )

Maps values from one `object` to a new `object` having the same keys.

```javascript
function transform( value, key ) {
    return key + value;
}

var obj1 = {
    'a': 1,
    'b': 2
};

var obj2 = mapValues( obj1, transform );
// returns { 'a': 'a1', 'b': 'b2' }
```

The `transform` function is provided three arguments:

-   **value**: object value corresponding to `key`.
-   **key**: object key.
-   **obj**: the input object.

</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

-   Key iteration order is **not** guaranteed, as `object` key enumeration is not specified according to the [ECMAScript specification][ecma-262-for-in]. In practice, however, most engines use insertion order to sort an `object`'s keys, thus allowing for deterministic return values.
-   The function only maps values assigned to **own** properties. Hence, the function does **not** map values for inherited properties.
-   The function **shallow** copies key values.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var mapValues = require( '@stdlib/utils-map-values' );

function transform( value, key ) {
    return key + ':' + value;
}

var obj1 = {
    'a': 'beep',
    'b': 'boop',
    'c': 'foo',
    'd': 'bar'
};

var obj2 = mapValues( obj1, transform );

console.dir( obj2 );
// => { 'a': 'a:beep', 'b': 'b:boop', 'c': 'c:foo', 'd': 'd:bar' }
```

</section>

<!-- /.examples -->

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</section>

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<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/utils-map-keys`][@stdlib/utils/map-keys]</span><span class="delimiter">: </span><span class="description">map keys from one object to a new object having the same values.</span>
-   <span class="package-name">[`@stdlib/utils-omit-by`][@stdlib/utils/omit-by]</span><span class="delimiter">: </span><span class="description">return a partial object copy excluding properties for which a predicate (function) returns a truthy value.</span>
-   <span class="package-name">[`@stdlib/utils-pick-by`][@stdlib/utils/pick-by]</span><span class="delimiter">: </span><span class="description">return a partial object copy containing properties for which a predicate (function) returns a truthy value.</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].

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[npm-url]: https://npmjs.org/package/@stdlib/utils-map-values

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[deno-url]: https://github.com/stdlib-js/utils-map-values/tree/deno
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[branches-url]: https://github.com/stdlib-js/utils-map-values/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-map-values/main/LICENSE

[ecma-262-for-in]: https://262.ecma-international.org/5.1/#sec-12.6.4

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[@stdlib/utils/map-keys]: https://www.npmjs.com/package/@stdlib/utils-map-keys

[@stdlib/utils/omit-by]: https://www.npmjs.com/package/@stdlib/utils-omit-by

[@stdlib/utils/pick-by]: https://www.npmjs.com/package/@stdlib/utils-pick-by

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