mapKeys
Map keys from one object to a new object having the same values.
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 tokeyobj: the input object
Notes
- Key iteration order is not guaranteed, as
objectkey 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
transformfunction should be a value which can be serialized as anobjectkey.
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' }