How can I parse time based tokens in JavaScript/Node.JS?

Question

I am trying to currently create a Discord bot which does temporary banning and for the most part I know how to handle this. The only issue is that I can't figure out how I would use an argument like 3w/2w/1y/etc to convert to a new time to create a timer. I've crawled all over Google to find an answer and I can't find even a slight hint or tip on how to accomplish this, maybe you guys might be able to point me in the right direction.

Answer 1

I would use a regex to parse the argument, and then map it to a date via milliseconds:

const mapping = {
  w: 7 * 24 * 60 * 60 * 1000,
  d: 24 * 60 * 60 * 1000,
  // whatever other units you want
};

const toDate = (string) => {
  const match = string.match(/(?<number>[0-9]*)(?<unit>[a-z]*)/);
  if (match) {
    const {number, unit} = match.groups;
    const offset = number * mapping[unit];
    return new Date(Date.now() + offset);
  }
}

Examples:

> toDate('3w')
2020-09-08T19:04:15.743Z
> toDate('2d')
2020-08-20T19:04:20.622Z