Time for the next installment in 256 JS Game Extensions. It’s been a while hasn’t it? Well don’t worry because here are four new crazy cool additions to the `Array`

class. This brings us up to 40!

Array::maxima = (valueFunction=Function.identity) -> @inject([-Infinity, []], (memo, item) -> value = valueFunction(item) [maxValue, maxItems] = memo if value > maxValue [value, [item]] else if value is maxValue [value, maxItems.concat(item)] else memo ).last() Array::maximum = (valueFunction) -> @maxima(valueFunction).first() Array::minima = (valueFunction=Function.identity) -> inverseFn = (x) -> -valueFunction(x) @maxima(inverseFn) Array::minimum = (valueFunction) -> @minima(valueFunction).first()

`Array#maxima`

is the core of this set, all the other methods are implemented based upon it. `maxima`

returns a list of the elements that have the maximum value for a given value function. The default value function is the identity function which returns the item itself. This will work great for integers or strings: anything that correctly works with the `>`

operator.

The value function can be overridden for example if you want to compute the maximum length word in a list you could pass in `(word) -> word.length`

The special case `maximum`

delegates to `maxima`

and returns only the first result. Similarly `minima`

delegates to `maxima`

but inverts the value function.

With these methods many problems that seem complex actually become quite a lot simpler by picking a value function and whether you want to maximize it or minimize it.