Question

For example (in JavaScript):

//Not that I would ever add a method to a base JavaScript prototype... 
//(*wink nudge*)...
Array.prototype.lastIndex = function() {          
  return this.length - 1;
}

console.log(array[array.lastIndex()]);

vs

console.log(array[array.length - 1]);

Technically speaking, the latter method uses one less character, but also utilizes a magic number. Granted, the readability may not really be affected in this case, but magic numbers suck. Which is better practice to use?

Answer 1

I’m of the opinion that 1 and 0 don’t really count as “magic numbers” in many cases. When you’re referring to the index of the last item (i.e. length - 1), that would definitely be one time where I would not consider 1 a magic number.