Comment by pfooti

So, I suppose you could do something like this instead.

    function leftPad(str, width, pad = ' ') {
      const actualWidth = Math.max(str.length, width);
      return `${pad[0].repeat(actualWidth - str.length)}${str}`;
    }

And that would do a leftPad pretty well, and be reasonably robust to stuff like the required width being less than the string width, the padding character being multiple characters long, and so forth. It doesn't do any type-checking of course.

It also doesn't work on older browsers - both string.repeat and template strings are new. You could fake it with string addition, but addition behaves oddly in the case your arguments are numerical, whereas template strings handle that. There's also a trick where you can say (new Array(desiredLength + 1)).join(' ') to make a string that is the appropriate length, but you've got OBOEs to worry about if you're not paying attention (Array.join puts the character between the elements, so you need an n+1 array for an n-length string). Also, at least on some browsers, Array.join is pretty cruddy, and you really ought to construct the string with an old-fashioned for loop.

Javascript has all kinds of weird corner cases and lots of browser compatibility problems. The fact that someone's written a decent implementation of something that should have been standard in the String object means I don't have to worry about it.

Of course, I do have to worry about stuff like losing access to left-pad when someone throws an npm tantrum, or dealing with future build issues if npm becomes untrustworthy. A cryptographically sound package manager seems like a reasonable want, especially after this week's issues.

But if your take-away from this whole problem is "meh, javascript devs are lazy", you're missing the point.