Why both the function calls return the same value?

Question

See the code segment below:

var o = {f:function(){ return this.a + this.b; }};
var p = Object.create(o);
o.a = 10;
o.b = 20;

console.log(o.f());  // output: 30
console.log(p.f());  // output: 30

The object p doesn't have property p.a and p.b then how p.f() return output 30. Is that prototype chain? Could anyone explain this? Thanks in advance.

Yes..just check the console here jsfiddle.net/sandenay/azjmxasu — Sandeep Nayak
– Sandeep Nayak, Commented Oct 14, 2015 at 5:45
Yes, it's the protootype chain. You can avoid it by shadowing a and b: p.a = p.b = 5; p.f() === 10 — Oriol
– Oriol, Commented Oct 14, 2015 at 5:46
To avoid that you can use var p = jQuery.extend({},o); in jQuery. — Sagar Khatri
– Sagar Khatri, Commented Oct 14, 2015 at 5:48

Arun P Johny · Accepted Answer · 2015-10-14 05:50:46Z

9

Here o is the prototype of the p object, so all the propeties of o is available in p.

So when you call p.f(), you will get the values assigned to o in this.a and this.b

edited Oct 14, 2015 at 5:50

answered Oct 14, 2015 at 5:44

Arun P Johny

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