can-map.js
function (callback, context) {
				var key, item;
			var keys = canReflect.getOwnEnumerableKeys(this);
			for(var i =0, len = keys.length; i < len; i++) {
			    key = keys[i];
			    item = this.attr(key);
			    if (callback.call(context || item, item, key, this) === false) {
			        break;
			    }
			}
			return this;
		}
function (callback, context) {
				var key, item;
			var keys = canReflect.getOwnEnumerableKeys(this);
			for(var i =0, len = keys.length; i < len; i++) {
			    key = keys[i];
			    item = this.attr(key);
			    if (callback.call(context || item, item, key, this) === false) {
			        break;
			    }
			}
			return this;
		}
### each loops through all the key-value pairs on this map.