Dynamic property assignment in JavaScript using string concatenation

Other Questions JavaScript
1

I’m building a JavaScript module for controlling audio equipment and need help with dynamic property names. Currently, I have code that handles each audio channel separately, but I want to make it more efficient by using variables to target specific channels.

Here’s what I have now:

if (path.includes('/audio_channel/5')) {
    var channelState = data.parameters[0].state;
    if (channelState === 1) {
        this.channel5status = "Active"
        console.log(`Audio Channel 5 status: ${this.channel5status}`);
    } else {
        this.channel5status = "Inactive"
        console.log(`Audio Channel 5 status: ${this.channel5status}`);
    }
}

What I want to achieve is something like this:

let channelNumber = ""
// Logic to find which channel needs updating...

let propertyName = "channel" + channelNumber + "status"
if (channelState === 1) {
    this[propertyName] = "Active"
    console.log(`Audio Channel ${channelNumber} status: Active`);
} else {
    this[propertyName] = "Inactive"
    console.log(`Audio Channel ${channelNumber} status: Inactive`);
}

Is this approach valid in JavaScript? What is this technique called when you build property names from strings?

2

Yeah, bracket notation works great! I use it constantly in audio projects - beats copy/pasting the same code for each channel. Just add validation first to check channelNumber isn’t empty or wonky, otherwise you’ll get properties like “channelstatus” instead of what you’re after.

3

Yeah, that’s computed property access (or dynamic property assignment) - totally valid JavaScript. I’ve done similar stuff with multi-channel mixing software where hardcoding every channel gets messy fast. Using this[propertyName] is the standard approach. From experience though, consider using a Map or object for channel states instead of individual properties. Something like this.channelStates[channelNumber] = "Active" is cleaner when you’ve got repeating data patterns. Also, you can pull the channel number straight from your path with path.match(/\/audio_channel\/(\d+)/)[1] - cuts out the separate channel detection logic. The bracket notation you’re using is core JavaScript stuff that’s everywhere in production code.

4

Yes, this works perfectly. You’re using bracket notation (or computed property access) - it’s a core JavaScript feature that lets you access object properties with dynamically built strings. I’ve used this exact pattern in audio apps where you’re managing multiple channels programmatically. The big win here is handling any number of channels with one code block instead of writing separate conditions for each channel. Just make sure to initialize your channel properties first so you don’t hit undefined values. You could also pull the channel number straight from your path string using regex or split methods instead of separate logic. This scales way better than hardcoding each channel, especially with mixing boards that have dozens of channels.