Uncaught ReferenceError: x is not defined |
Declare the variable with let, const, or var before using it |
Uncaught TypeError: x is not a function |
Make sure x is a function; check for typos or overwritten variables |
Uncaught TypeError: Cannot read property 'x' of undefined |
Check if the object exists before accessing its properties |
Uncaught SyntaxError: Unexpected token |
Fix syntax issues — check for extra commas, missing brackets, etc. |
Uncaught RangeError: Maximum call stack size exceeded |
Fix infinite loops or recursion; add base cases or break conditions |
Unexpected identifier / Unexpected string |
Double-check syntax and variable names |
Uncaught Error: Something went wrong |
Look for custom throw statements and trace the logic |
NetworkError / Failed to fetch |
Check the request URL, server status, and CORS settings |
NaN (Not a Number) |
Log your values and ensure they’re valid numbers before doing math |
undefined where a value is expected |
Make sure the variable or property has been properly initialized |
