Simplify Your JavaScript Code

Bad Practices

Changing Prototypes of Built-in Objects

You may have made a function on the String object prototype before similar to this:

String.prototype.reverse = (() => {
  // stuff like this.toString(), etc.
});

This is bad practice, however. You should instead use this:

function reverse(string) {
  // stuff like string.toString(), etc.
}

Useless Else-If

Let’s say you had a function like this:

function isZero(number) {
  if (number === 0) {
    return true;
  } else if (number !== 0) {
    return false;
  }
}

There’s a bad practice here. Can you spot it?

If you said that the else-if can be changed into an else, you’d be correct! If the check before hadn’t run, we know the number isn’t 0, so we don’t need to check that after we already know that the number isn’t 0.

Our function would now be:

function isZero(number) {
  if (number === 0) {
    return true;
  } else {
    return false;
  }
}