如何使用 JS 根据条件减去数组的元素后生成唯一值？

Question

如何检查 array1 中的项目是否存在于 array2 中，如果存在，则从 col5 中减去 col4 以输出待定数量。如果不是，则来自array1 的商品数量是待定数量。

let array1 = 
[
 [1, "Item A", "Food", 10, 0],
 [2, "Item B", "Food", 5, 0],
 [3, "Item C", "Food", 30, 0]
]

let array2 = 
[
 [1, "Item A", "Food", 5, 3],
 [3, "Item C", "Food", 10, 5]
]

预期结果

let res= 
[
 [1, "Item A", "Food", 10, 7],
 [2, "Item B", "Food", 5, 0],
 [3, "Item C", "Food", 30, 25]
]

我使用 for 循环启动它，但我想知道使用 map() 或 reduce() 会是什么样子？

let array1 = [
  [1, "Item A", "Food", 10, 0],
  [2, "Item B", "Food", 5, 0],
  [3, "Item C", "Food", 30, 0]
]

let array2 = [
  [1, "Item A", "Food", 5, 3],
  [3, "Item C", "Food", 10, 5]
]

let result = [];
for (let a = 0; a < array1.length; a++) {
  let item = [];
  for (let r = 0; r < array2.length; r++) {
    if (array1[a][0] == array2[r][0] && array1[a][1] == array2[r][1]) {
      let pendingQty = array1[a][3] - array2[r][4];
      if (pendingQty > 0) {
        item = [array1[a][0], array2[r][1], array2[r][2], array2[r][3], pendingQty];
      } else {
        item = array1[a];
      }
    }
    if (item.length === 0) {
      item = array1[a];
    }
  }
  result.push(item.slice());
}
console.log(result)

Answer 1

let a1 = [ [1, "Item A", "Food", 10, 0], [2, "Item B", "Food", 5, 0], [3, "Item C", "Food", 30, 0]];
let a2 = [ [1, "Item A", "Food", 5, 3], [3, "Item C", "Food", 10, 5]];
console.log(a1.map(e=>[...e.slice(0,4),e[3]-(a2.find(j=>j[1]===e[1])?.[4]??0)]));