@stdlib/utils-map-keys
v0.2.2
Published
Map keys from one object to a new object having the same values.
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mapKeys
Map keys from one object to a new object having the same values.
Installation
npm install @stdlib/utils-map-keys
Usage
var mapKeys = require( '@stdlib/utils-map-keys' );
mapKeys( obj, transform )
Map keys from one object
to a new object
having the same values.
function transform( key, value ) {
return key + value;
}
var obj1 = {
'a': 1,
'b': 2
};
var obj2 = mapKeys( obj1, transform );
// returns { 'a1': 1, 'b2': 2 }
The transform
function is provided three arguments:
key
: object keyvalue
: object value corresponding tokey
obj
: the input object
Notes
- Key iteration order is not guaranteed, as
object
key enumeration is not specified according to the ECMAScript specification. In practice, however, most engines use insertion order to sort anobject
's keys, thus allowing for deterministic return values. - The function only maps own properties. Hence, the function does not map inherited properties.
- The function shallow copies key values.
- The value returned by a
transform
function should be a value which can be serialized as anobject
key.
Examples
var mapKeys = require( '@stdlib/utils-map-keys' );
function transform( key, value ) {
return key + ':' + value;
}
var obj1 = {
'a': 'beep',
'b': 'boop',
'c': 'foo',
'd': 'bar'
};
var obj2 = mapKeys( obj1, transform );
console.dir( obj2 );
// => { 'a:beep': 'beep', 'b:boop': 'boop', 'c:foo': 'foo', 'd:bar': 'bar' }
See Also
@stdlib/utils-map-values
: map values from one object to a new object having the same keys.
Notice
This package is part of 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, see the main project repository.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.