"Could Not Find Function" Error in Web Development: What It Means and How to Fix It

When a browser console or runtime environment throws a "Could not find function" error, it's telling you that the code tried to call something that either doesn't exist, isn't accessible, or hasn't loaded yet. It's one of the most common JavaScript errors in web development — and one of the most misread, because the fix isn't always where the error points.

What "Could Not Find Function" Actually Means

At its core, this error is a runtime reference failure. When JavaScript executes a line like myFunction(), the engine looks up that name in the current scope chain — checking local scope, then parent scopes, then the global scope. If it doesn't find anything callable at that name, it throws a variation of this error, often phrased as:

• TypeError: myFunction is not a function
• ReferenceError: myFunction is not defined
• Could not find function myFunction (common in older browsers or specific frameworks)

These are distinct error types, but they all signal the same root problem: the function isn't where the code expects it to be.

Common Causes of This Error

1. The Function Hasn't Been Declared Yet

JavaScript is partially hoisted — meaning function declarations are moved to the top of their scope before execution, but const and let expressions are not. If you write: