在Javascript中使用关联数组重新组织JSON数据[重复]

Question

我有一些类似以下的数据：

let foodsArray = [
   {
        "food" : "fruit",
        "type" : "apple"
   } ,
   {
        "food" : "vegetable",
        "type" : "carrot"
   } ,
   {
        "food" : "vegetable",
        "type" : "lettuce"
   } ,
   {
        "food" : "fruit",
        "type" : "orange"
   } ,
]

我想重组如下：

newFoodsArray = [
    {
        "food" : "fruit",
        "type" : ["apple","orange"]
   } ,
   {
        "food" : "vegetable",
        "type" : ["carrot", "lettuce"]
   } ,
]

什么是迭代这些信息并构建我想要的结果的有效方法？我正在尝试这样的事情，但在语法上它不会飞。

for (let i = 0; i < foodsArray; i++) 
     newFoodsArray[foodsArray[i]["food"]].push(foodsArray[i]["type"]);

Answer 1

您可以使用reduce 轻松实现此结果。

let foodsArray = [
  {
    food: "fruit",
    type: "apple",
  },
  {
    food: "vegetable",
    type: "carrot",
  },
  {
    food: "vegetable",
    type: "lettuce",
  },
  {
    food: "fruit",
    type: "orange",
  },
];

const newFoodsArray = foodsArray.reduce((acc, { food, type }) => {
  const isExist = acc.find((el) => el.food === food);
  if (isExist) isExist.type.push(type);
  else acc.push({ food, type: [type] });
  return acc;
}, []);

console.log(newFoodsArray);