Higher-order messaging in JavaScript using Proxy

higher-order-messaging.js

// Inspired by this version for Ruby http://kbullock.ringworld.org/2007/03/26/higher-order-messaging/

if (typeof Proxy != "undefined") {
  try {
    Array.prototype.where = new Proxy(Array.prototype.filter, {
    
      apply: function(target, thisValue, args) {

        return new Proxy({}, {
          get: function(enumTarget, name) {

            return function() {
              var itemArgs = arguments;
              return target.call(thisValue, function(item) {
                return item[name].apply(item, itemArgs);
              });
            }

          }
        });

      }
    });
    
    // Example usage

    String.prototype.longerThan = function(num) {
      return this.length > num;
    }
    
    var arr = "Hello world this is Fabien".split(" ");
    
    var result = arr.where().longerThan(4);
    
    console.log(result); // ["Hello", "world", "Fabien"]

  } catch (e) {
    // Proxy object can exist but with a different form that is not constructible
    // calling new Proxy() in this case will throw an error
    console.log('Your environment does not support the new Proxies API.')
  }
}