JavaScript inheritance: when constructor has arguments

Question

Using pure JavaScript to do inheritance, this is what I usually do:

function A() {}
A.prototype.run = function () {};

function B() {}
B.prototype = new A;
B         


        

Answer 1

Although this is an old topic, I thought I'd respond anyway. Two ways to do it:

Although the Pseudo Classical way is the most popular, it has its down sides since it needs to call the parent constructor once in the child constructor and once while inheriting the prototype. Besides, the child's prototype will contain all the properties of the parent constructor which will anyway get overwritten when the child constructor is called. My personal choice is Prototypal Inheritance.

1. Pseudo Classical Inheritance:

function A(x, y) {} 
A.prototype.run = function () {};
function B(x, y) {
    A.call(this,x,y);
}
B.prototype = new A();
B.prototype.constructor = B;

2. Prototypal Inheritance:

function A(x, y) {}
A.prototype.run = function () {};
function B(x, y) {
    A.call(this,x,y);
}
B.prototype = Object.create(A.prototype);
B.prototype.constructor = B;