map function for objects (instead of arrays)

Question

I have an object:

myObject = { \'a\': 1, \'b\': 2, \'c\': 3 }

I am looking for a native method, similar to Array.prototype.map

Answer 1

The map function does not exist on the Object.prototype however you can emulate it like so

var myMap = function ( obj, callback ) {

    var result = {};

    for ( var key in obj ) {
        if ( Object.prototype.hasOwnProperty.call( obj, key ) ) {
            if ( typeof callback === 'function' ) {
                result[ key ] = callback.call( obj, obj[ key ], key, obj );
            }
        }
    }

    return result;

};

var myObject = { 'a': 1, 'b': 2, 'c': 3 };

var newObject = myMap( myObject, function ( value, key ) {
    return value * value;
});