Merge two sorted arrays

merge-sorted-arrays

function mergeArrays(arr1, arr2) {

    var out = [],
        i = 0,
        j = 0,
        length = arr1.length;
    
    while (arr2[j] < arr1[0]) {
        out.push(arr2[j++]);
    }

    for (; i < length; i++) {
        if (arr1[i] < arr2[j]) {
            out.push(arr1[i]);
        }
        else {
            while (arr2[j] < arr1[i]) {
                out.push(arr2[j++]);
            }
            if (arr1[i] != arr2[j]) {
                out.push(arr1[i]);
            }
        }
    }

    while (i < arr1.length) {
        out.push(arr1[i++]);
    }

    while (j < arr2.length) {
        out.push(arr2[j++]);
    }
    
    return out;
}

mergeArrays([2,3,4,5,9], [0,1,3,7])