how to call parent constructor?

Question

Let\'s say I have the following code snippet.

function test(id) { alert(id); }

testChild.prototype = new test();

function testChild(){}

var instance = new         


        

Answer 1

JS OOP ...

// parent class
var Test = function(id) {
    console.log(id);
};

// child class
var TestChild = function(id) {
    Test.call(this, id); // call parent constructor
};

// extend from parent class prototype
TestChild.prototype = Object.create(Test.prototype); // keeps the proto clean
TestChild.prototype.constructor = TestChild; // repair the inherited constructor

// end-use
var instance = new TestChild('foo');