Alright, here's my solution: https://jsfiddle.net/jf68mfj1/2/

I went for some solutions that may not be "good coding practices" depending on who you ask, because I wanted to explore JavaScript a bit further than a basic for-loop and if-statement.

Here's the main fizzBuzz function:

function fizzBuzz(num) {
    let returnValue = '';
    if (num % 3 === 0) returnValue += 'Fizz';
    if (num % 5 === 0) returnValue += 'Buzz';
    return returnValue || String(num);
}

Like others I concatenate Fizz and Buzz so I don't need a third if-statement. As a bonus I use JavaScript's type coercion to check if returnValue is truthy, and if it's not (an empty string '' is falsy) I return the original number. Initially I returned it as an integer too, but returning mixed types is bad practice and in fact actually broke my tests, so I return it a as string now too.

Fizzing from 0 to 100 I do with this method:

function fizzTo100() {
    const allFizzBuzzes = [...Array(100).keys()].map(fizzBuzz);
    output(allFizzBuzzes.join('\n'));
}

The first line looks a bit like a hack. What I do is create an array of 100 length and then take the keys from that array. All the values are still undefined, but the keys are 0-100. The result of keys() is an iterable though, so I turn it back into an array using the spread operator in a new array [...x].
Now I have an array of 1-100 that I can map to fizzBuzz.

See and test my code here: https://jsfiddle.net/jf68mfj1/2/

If anyone is interested in more details let me know and I'll write a blog post about it. Not going throught that effort if nobody cares though ;)