This has happened to me enough times now that I should know better.

I have a constant:

const statuses = {
  OK: 0,
  ERROR: 1
};

I use this constant to check the status of something:

let currentStatus = null;
Something.getStatus().then((status) => {
  currentStatus = status;
});

// Then later on..

if (currentStatus && currentStatus === statuses.OK) {
  // do something.
}

The if statement will never actually work, because in the statuses constant OK is 0, which is falsy, meaning that the if (currentStatus part won’t be true.

It’s very easy to solve this, just use strings or positive values:

const withNumbers = {
  OK: 1,
  ERROR: 2
};

const withStrings = {
  OK: '0',
  ERROR: '1'
};

Me, after this has happened for the third time, necessitating this post: