array.forEach的怪异行为

Question

I have an array of objects:

var conversions = [
    { regex: ..., names: [ ... ] },
    ...
];

I loop through each conversion object and pass them to a certain function:

conversions.forEach(function(conv) {
    // function selection logic

    var result = func(message, conv); // func is the selected function, message is defined before

    // result logic
}

The loop works fine for all the objects in the array, but after the last object, a weird object is passed to the callback which is not part of my array. Adding console.log(conv); at the very beginning of the callback prints out all the conversions correctly, but the last weird object is printed out as epäluku undefined . "Epäluku" is a bad Finnish translation for NaN , which means the output is the same as NaN.toLocaleString() + " " + undefined .

I haven't been able to figure out why this odd object is there, or how to filter it. I've tried checking it against null and undefined but neither did the trick. I've even tried checking it against NaN.toLocaleString() + " " + undefined but that didn't work either.

This is part of a userscript, running in Chrome using Tampermonkey.

Answer 1

Turns out the issue was my code all along. In an unrelated function I was adding elements to the conversions array rather than the correct array within that function.