2.1 KiB
2.1 KiB
Non-Index Keys
Return an array of an object's own enumerable property names which are not integer indices.
Usage
var nonIndexKeys = require( '@stdlib/utils/nonindex-keys' );
nonIndexKeys( obj )
Returns an array
of an object's own enumerable property names which are not integer indices.
var arr = [ 1, 2, 3 ];
arr.a = 'foo';
arr.b = 'bar';
var keys = nonIndexKeys( arr );
// e.g., returns [ 'a', 'b' ]
Notes
- Name 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 extraction. - In contrast to the built-in
Object.keys()
, if providednull
orundefined
, the function returns an emptyarray
, rather than throwing an error.
Examples
var nonIndexKeys = require( '@stdlib/utils/nonindex-keys' );
function Foo() {
this[ 0 ] = 3.14;
this.beep = 'boop';
this.a = {
'b': 'c'
};
return this;
}
Foo.prototype.foo = [ 'bar' ];
var obj = new Foo();
var keys = nonIndexKeys( obj );
console.log( keys );
// e.g., => [ 'beep', 'a' ]