Understanding Javascript Chaining Patterns

Question

I ran this code into the console and tried calling:

obj.foo().bar().coo().moo();

This was my previous code:

    function bar() {
  this.coo = function () {
    this.moo = function () {
      console.log("yay");
    }
  }
}

obj = {
  foo : function () {this.bar = bar}
};

The error that returned was "TypeError: Cannot read property 'bar' of undefined". Although, when I wrote:

obj.foo();
obj.bar();
obj.coo();
obj.moo();

It worked fine. Why didn't the first call using method chaining not work as if I was separately calling each method.

you want to un-nest those methods...

dandavis
– dandavis

2014-10-18 19:38:22 +00:00
Commented Oct 18, 2014 at 19:38 — dandavis
– dandavis, Commented Oct 18, 2014 at 19:38

Scimonster · Accepted Answer · 2014-10-18 19:30:14Z

4

You don't return anything. You need to add return this at the end of each of your functions in order to have an object to chain.

answered Oct 18, 2014 at 19:30

Scimonster

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Scimonster Over a year ago

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