Javascript toLowerCase() undefined error

Question

I know this has been put out too many times, but none of the questions fix the problem I have. It gives me the following error every time I run the function:

TypeError: Cannot read property 'toLowerCase' of undefined

Here's the code it's running:

global.toId = function(text) {
    return text.toLowerCase().replace(/[^a-z0-9]/g, '');
};

Answer 1

In ES2020, you can use optional chaining (?.)

global.toId = function(text) {
    return text?.toLowerCase().replace(/[^a-z0-9]/g, '');
};