I’m struggling with implementing recurring function calls in my Spotify app. When I try timer = setInterval(myCallback(), 1000); the callback only executes one time instead of repeating every second like it should.
Then I attempted using a string approach: timer = setInterval("myCallback()", 1000); and while this seems to trigger repeatedly, I get Uncaught ReferenceError: myCallback is not defined thrown every second.
What am I doing wrong here? How should I properly set up repeating function execution?
You’re hitting a classic JavaScript gotcha with function references vs calls. When you add parentheses after myCallback, you’re executing it immediately and passing the result to setInterval - that’s why it only runs once. The string approach fails because the callback runs in global scope where myCallback isn’t accessible. I hit this same issue building a music visualizer that synced with playback. Just pass the function reference directly: timer = setInterval(myCallback, 1000); - no parentheses. Need to pass parameters? Wrap it in an arrow function: timer = setInterval(() => myCallback(param), 1000); instead of using strings. This keeps proper scope and prevents reference errors.
The issue is JavaScript calls myCallback() immediately when you write setInterval(myCallback(), 1000), then passes its undefined return value to setInterval. Since there’s no actual function to repeat, it just runs once and stops. I hit this same bug when setting up periodic API calls for progress tracking. Just drop the parentheses - setInterval(myCallback, 1000) passes the function reference instead of executing it right away. The string approach doesn’t work because setInterval runs strings in global scope, where it can’t see your local functions. Stick with function references - cleaner code and proper scoping.
You’re making a classic mistake with the first approach. When you write myCallback() with parentheses, you’re running the function right away and passing its return value to setInterval instead of the function itself. Just use timer = setInterval(myCallback, 1000); without the parentheses. That way setInterval can call it repeatedly.
Skip the string approach entirely - it causes scope problems and reference errors. Stick with the function reference method. It’s cleaner and way more reliable for handling periodic tasks.
yeah, ive been there! you gotta just pass the function without the () like setInterval(myCallback, 1000). if you use the () it calls it right away. the string method is a no-go too, it messes with scope! that’s why ur seeing that error.
This parentheses thing used to trip me up all the time when I first started with web audio timers. The issue is JavaScript runs myCallback() right away and setInterval gets whatever that function returns - usually just undefined instead of the actual function. I made this exact mistake building a tempo analyzer that had to constantly check Spotify’s playback position. What finally made it click was realizing setInterval wants a function reference, not a function call. Just use timer = setInterval(myCallback, 1000); and JavaScript handles calling it every second. That string method you tried is old and messy - it runs in global scope where your local functions aren’t accessible.