merge.js

// write a function that merges two unsorted arrays

function merge(leftArr,rightArr){
	let merged = [];
	let i = 0;
	let j = 0;
	// while we are still inbounds for both arrays
	while(i < leftArr.length && j < rightArr.length){
		if(leftArr[i] < rightArr[j]){
			merged.push(leftArr[i]);
			i++;
		}else if(rightArr[j] < leftArr[i]){
			merged.push(rightArr[j]);
			j++;
		}
	}
// if either counter is out of bounds, the other array has the remaining numbers which can simply be appended
	if( i < leftArr.length ){
		merged = merged.concat(leftArr.slice(i));
	}
	else if ( j < rightArr.length){
		merged = merged.concat(rightArr.slice(j));
	}

	console.log(merged);
} 

merge([2,4,5],[1,3,7]); // [1,2,3,4,5,7]