src/lowerdash.js
function keyOf(obj, value){
		for(var key in obj)
			if(Object.prototype.hasOwnProperty.call(obj, key) && obj[key] === value)
				return key;

		return null;
	}
function keyOf(obj, value){
		for(var key in obj)
			if(Object.prototype.hasOwnProperty.call(obj, key) && obj[key] === value)
				return key;

		return null;
	}
function keyOf ( obj , value ) { for ( var key in obj ) if ( Object . prototype . hasOwnProperty . call ( obj , key ) && obj [ key ] === value ) return key ; return null ; }
Retrieve object's key paired to given property
@method keyOf
@param {Object} obj			Object to get key from
@param {Mixed} value		Value corresponding to key
@return {String}			Key or null if no key was found
Retrieve object s key paired to given property