// single  liner codes
const all = (arr, fn=Boolean) => arr.every(fn);

all([1,2,3,4,5], x => x > 0);

// how can we check all arrary elm are equal

const allEqual = arr => arr.every(val => val === arr[0])

allEqual([1,1,1,1,1,]);
allEqual([1,2,3,4]);



const countOccurrences = (arr, val) => arr.reduce((a, v) => (v === val ? a + 1 : a), 0);

countOccurrences([1, 1, 2, 1, 2, 3], 1); // 3