编辑代码

function updateInventory(arr1, arr2) {
    // All inventory must be accounted for or you're fired!
    var map1 = new Map(change(arr1));
    //var map2 = new Map(change(arr2));
    for (var i = 0; i < arr2.length; i++) {
        var name = arr2[i][1];
        var num = arr2[i][0];
        if (map1.get(name) == undefined)
            map1.set(name, num);
        else
            map1.set(arr2[i][1], num+map1.get(name));
    }
   var arr = Array.from(map1); // 二维数组
   arr.sort();
    //  return new Map(arr1);
  return change(arr);
}
function change(arr) {
    
    for (var i = 0; i < arr.length; i++) {
        console.log("arr"+i+":"+arr[i]);
        var a = arr[i][0];
        arr[i][0] = arr[i][1];
        arr[i][1] = a;
    }
    console.log("arrED:"+arr);
    return arr;
}
// Example inventory lists
var curInv = [
    [21, "Bowling Ball"],
    [2, "Dirty Sock"],
    [1, "Hair Pin"],
    [5, "Microphone"]
];

var newInv = [
    [2, "Hair Pin"],
    [3, "Half-Eaten Apple"],
    [67, "Bowling Ball"],
    [7, "Toothpaste"]
];


console.log(updateInventory(curInv, newInv));