Javascript create dynamic object inside object and access its properties

Question

I am getting the name of the user everytime the script is called and storing it in a variable called name

And I have a object which is initially null and I want it to be populated based on the name that I read.

I have this object

var usernames = {
    name1: {
        name: "ajey",
        room: 1,
        isStudent: true,
        isTeacher: false
    },
    name2: {
        name: "ajey-teacher",
        room: 1,
        isStudent: false,
        isTeacher: true
    },
    name3: {
        name: "batman",
        room: 2,
        isStudent: true,
        isTeacher: false
    }
};

Later I would print all the objects along with its key and value in the usernames object like,

for(var i in usernames) {
 console.log(i.name1.name);
}

Here is the fiddle I am working on but I am having some issues. Demo

Satpal · Accepted Answer · 2014-01-16 06:13:50Z

2

Use

for (var i in usernames) {
    console.log(usernames[i].name);
}

DEMO

answered Jan 16, 2014 at 6:13

Satpal

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1 Comment

Ajey Over a year ago

Got it. And how do I create the name1, name2, name3 objects and so on dynamically ? based on the variable name

Barmar · Accepted Answer · 2014-01-16 06:24:31Z

2

The loop should be:

for (var i in usernames) {
    console.log(usernames[i].name);
}

When you use for-in, the variable is set to the property name. To use a dynamic property name, you have to use bracket syntax; dot syntax is only for literal properties.

You can also use bracket syntax to create properties dynamically:

usernames['name'+i] = {
    name: "batman",
    room: 2,
    isStudent: true,
    isTeacher: false
};

edited Jan 16, 2014 at 6:24

answered Jan 16, 2014 at 6:13

Barmar

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5 Comments

Ajey Over a year ago

Got it. And how do I create the name1, name2, name3 objects and so on dynamically ? based on the variable name

Barmar Over a year ago

Added explanation of that.

Barmar Over a year ago

Although I wonder why you're using an object. Usually when you find yourself using names with consecutive numbers like this, you should actually be using an array.

Ajey Over a year ago

Actually I am building a chat application in node and socket. So initially when the client connects to the chat, I am storing all the details like name, room no, role inside an object(which is his username) and this object is stored inside a global usernames object. So with this later I can process in which room or role the user belongs to. Is this a good approach ?

Barmar Over a year ago

OK, that makes sense. These names were just examples, in real life they wouldn't have a pattern like this.

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