Given an array of integers and a number k, where 1 <= k <= length of the array, compute the maximum values of each subarray of length k.

array-max.js

const max = arr => Math.max(...arr)

const calc = len => (len / 2 + 1)

const floor = num => Math.floor(num)

const add = arr => item => arr.push(item)

const slice = arr => start => end => arr.slice(start, end)

const main = (arr) => (k) => {
	const length = calc(floor(arr.length))
	const result = []
	
	for ( let i = 0; i < length; i++ ) {
		add( result )( max( slice(arr)(i)(i + k) ) )
	}
	
	return result
}

main( [10, 5, 2, 7, 8, 7] )( 3 ) // return: [10, 7, 8, 8]