Object.map.js

Array.map for Object in JavaScript. Map both an object’s keys and values.

Usage

By default, will allow calling Object.map (obviously, as a non-enumerable property).

If you're terrified about augmenting prototypes of natives zomg ruin on us all, just set the shouldAugmentObjectPrototype param to false on the last line. The enclosing IEFE will then return the mapObject function with the source object as its first parameter, so you can call it however you want.

/**
*@param	{Function|String}	[valueMapper = pass-through]	The function to map the value from the source's value. Will be passed the current value, the original key, and the mapped key. If a string, will be set to an accessor for that attribute.
*@param	{Function|String}	[keyMapper = pass-through]	The function to map the key from the source's key. Will be passed the original key and the original value. If a string, will be set to an accessor for that attribute.
*@throws	TypeError	If one of the mapper is an illegal type.
*@returns	{Object<String,String>}
*/
Object.map(valueMapper, keyMapper);

Example

var source = { a: 1, b: 2 };
function sum(x) { return x + x }

source.map(sum);            // returns { a: 2, b: 4 }
source.map(undefined, sum); // returns { aa: 1, bb: 2 }
source.map(sum, sum);       // returns { aa: 2, bb: 4 }

License

MIT: Do whatever you want as long as you don't sue me nor prevent others to reuse this piece of software. Also, credit is always appreciated ;)