CODEWITHSUNDEEP
node.js
user1748253
user1748253

Reputation: 204

Node.js Inheritance

I have inherited a class from another JS, and added few prototype function over Parent functions. When i create a new instance of child, i want to call the constructor of parent. Please suggest a way.

Parent 

function Parent() { .. } 
    Parent.prototype.fn1 = function(){};
    exports.create = function() {
    return (new Parent());
};

Child 

var parent = require('parent');
Child.prototype = frisby.create();
function Child() { .. } 
Child.prototype.fn2 = function(){};
exports.create = function() {
    return (new Child());  
};

Upvotes: 1

Views: 3484

Answers (3)

Knase
Knase

Reputation: 1274

You can use module util. Look simple example:

    var util = require('util');

function Parent(foo) {
    console.log('Constructor:  -> foo: ' + foo);
}

Parent.prototype.init = function (bar) {
    console.log('Init: Parent -> bar: ' + bar);
};

function Child(foo) {
    Child.super_.apply(this, arguments);
    console.log('Constructor: Child');
}


util.inherits(Child, Parent);

Child.prototype.init = function () {
     Child.super_.prototype.init.apply(this, arguments); 
     console.log('Init: Child');
};

var ch = new Child('it`s foo!');

ch.init('it`s init!');

Upvotes: 1

Teemu Ikonen
Teemu Ikonen

Reputation: 11929

Parent (parent.js)

function Parent() {
}

Parent.prototype.fn1 = function() {}
exports.Parent = Parent;

Child

var Parent = require('parent').Parent,
    util = require('util');

function Child() {
   Parent.constructor.apply(this);
}
util.inherits(Child, Parent);

Child.prototype.fn2 = function() {}

Upvotes: 0

Anatoliy
Anatoliy

Reputation: 30103

First of all, do not export create method, export constructor (Child, Parent). Then you will be able to call parent's constructor on child:

var c = new Child;
Parent.apply(c);

About inheritance. In node you can use util.inherits method, which will setup inheritance and setup link to superclass. If you don't need link to superclass or just want to inherit manually, use proto:

Child.prototype.__proto__ = Parent.prototype;

Upvotes: 0

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