javascript - Delay to next function in method chain

Question

I am trying to learn more about Method chaining in Javascript and would like to know the proper way to create a delay with no jQuery to the next function in the chain:

var foo = function() {
    this.delay = function(per) {
        setTimeout(start, per);
        return this;
    };
    this.start = function() {
        alert('start!');
    };
};

var bar = new foo().delay(1000).start();

Answer 1

This isn't easy to do. jQuery uses a specific queue system.

Suppose you want to do it without jQuery, you would have to implement a queue yourself.

For example this very simplistic implementation :

var foo = function() {
    var queue = [];
    var timer;
    this.delay = function(per) {
      timer = setTimeout(function(){
        timer = 0;
        var f;
        while (f = queue.shift()) f();
      }, per);
      return this;
    };
    this.addFunction = function(f) {
      if (timer) queue.push(f);
      else f();
      return this;
    };
    this.start = function() {
       this.addFunction(function(){alert('start')});
       return this;
    };
};

Demonstration

---

If you want to chain another function not defined in foo, you may do

var bar = new foo().delay(3000).start()
    .addFunction(function(){alert("another chained one")});

Demonstration