cemerick - 4 months ago 29

Javascript Question

In short, this works:

`[1, 2, 3].reduce(function (a, b) { return Math.max(a, b); });`

=> 3

But this doesn't:

`[1, 2, 3].reduce(Math.max);`

=> NaN

Pure puzzlement.

This is in Firefox 3.5.9, which I presume is using the mozilla standard implementation of reduce, FWIW.

Answer

`Math.max`

can be used as a higher-order function. The problem is `.reduce`

will call the function with 4 arguments:

```
Math.max(accumulator, value, index, the_array)
```

here is `the_array`

is an array, so `Math.max`

returns NaN. I don't think there's simpler way to discard the last 2 arguments.