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JavaScript Node.js Basics (2014) Building a Command Line Application Perfecting: Getting Multiple Profiles

Nikolay Komolov
Nikolay Komolov
23,033 Points
Posted by Nikolay Komolov
Nikolay Komolov
23,033 Points

Passing a variable's contents to an object's property reference

Hello everybody! Could you help me, please?

I created a variable 'topic' and trying to pass its value as the property of the object (profile.points.topic). 

var topic = 'Ruby';    
printMessage(username, profile.badges.length, profile.points.topic, topic);

It looks for 'topic' property which doesn't exist, instead of looking for the contents of the variable. How can I fix it?

Thanks!

2 Answers

miikis
miikis
44,957 Points

Hey Nikolay,

You could set the property directly — like this:

var topic = 'Ruby';
profile.points.topic = topic;

console.log(profile.points.topic); // This would now evaluate to: 'Ruby'

Is that what you were asking?

Nikolay Komolov
Nikolay Komolov
23,033 Points
Nikolay Komolov
Nikolay Komolov
23,033 Points

Thanks for the help! I was looking for a solution to replacing '.topic' part with the variable's contents. I want to access the property like this: profile.points.[var contents]. For instance, if topic = 'JavaScript', this line should become profile.points.JavaScript. :)

miikis
miikis
44,957 Points

Assuming an object exists that looks something like this:

var profile.points = {
    'ruby': 78273,
    'javascript': 12334
}

Then, you could do this:

console.log(profile.points["javascript"]) // This would evaluate to: 12334

This "array-like" syntax is yet another way to access an object's properties in JavaScript. Does that answer your question?

miikis
miikis
44,957 Points

You could also do this:

var profile.points = {
    'ruby': 78273,
    'javascript': 12334
}
var topic = 'ruby';

console.log(profile.points[topic]); // This would evaluate to 78273
Nikolay Komolov
Nikolay Komolov
23,033 Points
Nikolay Komolov
Nikolay Komolov
23,033 Points

Yes, exactly! Thanks a lot :)

miikis
miikis
44,957 Points

No problem :)