@stdlib/utils/map-values/README.md

Standard utilities.

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# mapValues

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

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## 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.

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## 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.

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## 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' }
```

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* * *

## 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>

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

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[@stdlib/utils/map-keys]: https://github.com/stdlib-js/utils/tree/main/map-keys

[@stdlib/utils/omit-by]: https://github.com/stdlib-js/utils/tree/main/omit-by

[@stdlib/utils/pick-by]: https://github.com/stdlib-js/utils/tree/main/pick-by

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