node runtime ai_generated true

TypeError: x is not a function

ID: node/typeerror-not-a-function

Also available as: JSON · Markdown
96%Fix Rate
97%Confidence
50Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
20 active — — —

Root Cause

Attempting to call something that isn't a function — usually a wrong import or undefined variable.

generic

Workarounds

  1. 95% success Check the import: the function may be a named export, not default 
    import { fn } from 'mod' vs import mod from 'mod'; mod.fn()
  2. 88% success Verify the API — the method may have been renamed or removed in a newer version 
    Check the package changelog and documentation

    Sources: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Not_a_function

Dead Ends

Common approaches that don't work:

  1. Wrapping in try/catch and calling a fallback 65% fail

    Masks the import/API issue; fallback may not be equivalent

  2. Adding typeof checks before every function call 70% fail

    Boilerplate; hides the root cause

Error Chain

Frequently confused with: