Image by Nicolas Poupart

I'm working on some cookie code where the cookie needs to expire one year from now. Well, not *exactly*. The full story is that the cookie needs to expire *no later than one year from now*.

This involves the following snippet of JavaScript:

```
date.setTime(date.getTime()+(365*24*60*60*1000));
```

That's the number of days in a year, times the number of hours, times... well, you get the picture. Computers are weird: they calculate dates as the number of milliseconds which have passed since New Year 1970.

That calculation above is trivial for a computer and results in the number 31,536,000,000. But could I express it in fewer bytes? My first thought was to express it as a power, using `Math.pow()`

. `Math.pow()`

takes two parameters: the number and the exponent. Perhaps there was a pairing of such numbers which would use the smallest amount of bytes and create a number which was *slightly* less than 31,536,000,000.

I did the dumb thing: I found a cube-root calculator and started plugging in exponents, until I found a number which rounded down well. The initial number was 9.00179. The exponent was 11. Rounding this down led to a cookie which would expire two days before the deadline.

Excitedly, I updated the code, to see how many bytes I would save:

```
date.setTime(date.getTime()+Math.pow(9,11));
```

I glanced at the calendar, and remembered what happened on this day, nineteen years ago. Here's some more numbers: 2,977 people died that day. More than 6,000 were injured. Suddenly the maths seemed less fun.

Note that 9^{11} would produce this rough approximation of the number of milliseconds in a year any time it was calculated. I just happened to stumble upon this today.

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