bIncludesA.js

/**
 * do the array b includes all elements from the array a
 * 
 * @param {Array} a
 * @param {Array} b
 * @param {Boolean} [unsorted=false] are the arrays unsorted
 * 
 * @returns {Boolean}
 */
function bIncludesA ( a, b, unsorted ) {

    if ( unsorted ) {
        a = a.sort();
        b = b.sort();
    }

    var aPointer = bPointer = 0,
        aLength = a.length,
        bLength = b.length,
        matches = 0;

    while ( aPointer < aLength && bPointer < bLength ) {

        if ( a[aPointer] === b[bPointer] ) {

            matches++;
            aPointer++;
            bPointer++;
            continue;

         } else if ( a[aPointer] > b[bPointer] ) {

            bPointer++;
            continue;

        }

        break;
    }

    return aLength === matches;
}