Javascript Methods/Objects

Question

I think I finally wrapped my head around understanding how methods, constructor functions, and objects work. Could someone please review my code, and let me know if I using the correct names and syntax? Thanks a ton!

function objectConstructor (arg1, arg2) {
     this.property1 = arg1;
     this.property2 = arg2;
     this.methodName = functionName;
}
function functionName() {
     console.log(this.property1 + ' ' + this.property2);   
}

var object1 = new objectConstructor('value1','value2');

console.log(object1.property1);
console.log(object1.methodName());

Why don't you just paste this into a console and see if it runs? Since you're only asking about syntax. — rvighne
– rvighne, Commented Feb 1, 2014 at 23:12
By the convention, constructor functions names should start with an uppercase letter. — Wiktor Zychla
– Wiktor Zychla, Commented Feb 1, 2014 at 23:14
you didn't understand that javascript is a prototype based language and in the way you do it it's very memory intensive and slow. Prototype-based_programming — bitWorking
– bitWorking, Commented Feb 1, 2014 at 23:17
I agree and understand javascript is a prototype based language. This example was just for my own understanding on how everything works as a whole. I would never uses these names in a project or anything that would be insane! :) — sneak972
– sneak972, Commented Feb 1, 2014 at 23:23
This question appears to be off-topic and belongs on codereview.stackexchange.com — DanMan
– DanMan, Commented Feb 1, 2014 at 23:38

bitWorking · Accepted Answer · 2014-02-01 23:48:59Z

0

Use prototype functions. Else your inner functions get copied with every instance.

function Person(firstName, lastName)
{
    this.firstName = firstName;
    this.lastName = lastName;
}

Person.prototype.getFullName = function()
{
    return this.firstName+' '+this.lastName;
}

var person1 = new Person('foo', 'bar');
console.log(person1.getFullName());

There are many other patterns which for example prevent the pollution of the global scope or allow a more class like approach. (Object literal, Module Pattern, Self-Executing Anonymous Functions)

The same example with the module pattern:

var Person = (function()
{
    var Person = function(firstName, lastName)
    {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    Person.prototype.getFullName = function()
    {
        return this.firstName+' '+this.lastName;
    }

    return Person;

})();

var person1 = new Person('foo', 'bar');
console.log(person1.getFullName());

edited Feb 1, 2014 at 23:48

answered Feb 1, 2014 at 23:36

bitWorking

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1 Comment

bitWorking Over a year ago

@sneak972 I've add a module pattern example.

Manuel Hoffmann · Accepted Answer · 2014-02-01 23:54:27Z

0

Methods of Javascript classes should be defined as prototype:

var CustomObject = function (arg1, arg2) {
     this.property1 = arg1;
     this.property2 = arg2;
};

CustomObject.prototype.functionName = function() {
     console.log(this.property1 + ' ' + this.property2);   
};

var object1 = new CustomObject("value1","value2");

Everything else seems fine to me though.

edited Feb 1, 2014 at 23:54

answered Feb 1, 2014 at 23:35

Manuel Hoffmann

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3 Comments

DanMan Over a year ago

Messing with the Object prototype is considered bad practice.

sneak972 Over a year ago

You're absolutely right thanks Manuel! I'm still learning prototypes, but thank you for the example.

Manuel Hoffmann Over a year ago

@DanMan Object should be the name of a custom type here. I forgot that there was the javascript-"Object".

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