How to implement apply pattern in Javascript

Question

What is apply invocation pattern in Javascript in reference to function invocation patterns and how can I use it? What are the benefits of using this invocation pattern.

Answer 1

You can also use call/apply for inheritance.

function Client (id) {
  this.id = id;
  this.name = "Client" + id;
}

Client.prototype = {
    constructor: Client

  , toString: function () {
      return this.name;
    }
};

function WebClient (id) {
  Client.call (this, id);
}

WebClient.prototype = new Client ();

WebClient.prototype.constructor = WebClient;

WebClient.prototype.ping = function () {
  // do stuff
};

Notice Client.call (this, id); This executes Client using the this instance that a new WebClient would create. Thus when

  this.id = id;
  this.name = "Client" + id;

are executed inside Client the WebClient instance is getting assigned those properties.