我正在嘗試通過首先創建對象來使數據更易于管理，從而將“新發貨”數組與當前庫存數組合并。因此，任何相同的物品都會添加到庫存中的任何現有物品中。.sort 運行，但 flat 似乎不執行任何操作。我懷疑存在某種與我如何制作數組和弄亂索引有關的問題？function updateInventory(arr1, arr2) {    let invObj = {}    let updateObj = {}    let result = []    arr1.forEach( x => invObj[x[1]] = x[0])    arr2.forEach( x => updateObj[x[1]] = x[0])    for(let key in updateObj) {        if (invObj[key]) {            invObj[key] += updateObj[key]        } else {            invObj[key] = updateObj[key]        }    }    result =  Object.keys(invObj).map(key=>[invObj[key],key])    .sort((a,b)=>{    // attempting to sort inventory alphabetically here as required by my course's test        return a[1] - b[1]    })    return result}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));