What is the valid Javascript syntax for creating an object by using Object Literal Notation?

Question

I'm learning Javascript track in codecademy.com. And I'm confused about creating object by using "Object Literal Notation".

Here syntax1, in the hint section the syntax is:

var friends = {
    bill: {},
    steve: {}
};

We need those curly braces to contain keys' values within the object's curly brace.

BUT, in syntax2, the syntax is:

var myObject = {
    key: value,
    key: value,
    key: value
};

See, no need for curly braces container within the object's curly brace. As I did the exercise we only required to: direct input for numbers and functions, or within quotation for strings, or within square brackets for arrays.

Can someone kindly share their knowledge and time to tell me why we have the difference or which one is the correct syntax?

It's clearly stated: "Use your friends' names as the keys for the empty objects." — PM 77-1
– PM 77-1, Commented Jul 29, 2014 at 0:30
@all: Thanks guys, for all your fast respond. I need some time to understand and try'em. — Alec Hutomo
– Alec Hutomo, Commented Jul 29, 2014 at 0:41

GregL · Accepted Answer · 2014-07-29 23:59:06Z

3

The "Object Literal Notation" just means the following format:

var myObject = {
    key1: <value1>,
    key2: <value2>,
    // ...
    keyN: <valueN>
};

where <valueX> can be any JS value, like a boolean, a number, a string or even another Object (which is indicated by the same { key1: <value1> ... } syntax).

An empty object is just one that has no keys (properties) and thus looks like { } (space is optional).

edited Jul 29, 2014 at 23:59

answered Jul 29, 2014 at 0:34

GregL

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Thiago Custodio · Accepted Answer · 2014-07-29 12:50:31Z

1

It depends on what will be the content of your variables:

synthax1:

var obj = {
    name: "Thiago",
    currentYear : 2014
};

synthax2:

    var obj = {
        name: "Thiago",
        skills: {
           key: "JS",
           value: 1
        }

};

you can initialize with [] and it will be an array.

edited Jul 29, 2014 at 12:50

answered Jul 29, 2014 at 0:31

Thiago Custodio

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2 Comments

GregL Over a year ago

In your haste, you made a syntax error with your "syntax1" example.

Alec Hutomo Over a year ago

Is the error is equal sign in "currentYear = 2014", Greg ? Sorry, but i'm happy to know a bit here and there as my learning goes onward.

SLaks · Accepted Answer · 2014-07-29 00:30:58Z

0

It depends what you want the values to be.

{} is an empty object; other literals are other values.

answered Jul 29, 2014 at 0:30

SLaks

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