oop - how prototype properties are delegated to sub class from super class in javascript -


please me understand following code snippet. 

var ob = {a:20,b:30}; object.prototype.c = '40'; (var x in ob){     console.log(x); // log a,b,c in console } var keys = object.keys(ob) ; console.log(keys); // log a,b in console

my question , how putting property 'c' on prototype of 'object' make available 'ob' ?

edit: want know default constructor function called when try create object , basic responsibilities performed constructor ?

an object literal ({}) inherit object.prototype. object.prototype.c = '40'; sets c property on object's prototype, objects inheriting object able access property. properties defined on object's prototype accessible on objects inheriting it.

the difference between for (var x in ob) , object.keys(ob) object.keys(ob) return properties of ob object, whereas for (var x in ob) traverse prototype chain , find c property on object's prototype.

by default, no properties defined on object's prototype included in for-in loop not enumerable. added property enumerable default.


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