根据 JavaScript 中的属性值从对象数组中删除重复项

Question

如何根据 name 属性从数组 someArray 中删除重复项，条件是如果 name 对于两个元素相同但是对于其中一个 type 是 new，原始的（没有类型 new）将被保留？

someArray = [{id: 1, name:"apple"}, {id: 2, name:"mango"}, {id: 3, name:"apple", type: "new"}, {id: 4, name:"orange"}, {id: 5, name:"orange", type: "new"}, {id: 6, name: "pineapple", type: "new"}]

到

[{id: 1, name:"apple"}, {id: 2, name: "mango"}, {id: 4, name:"orange"}, {id: 6, name: "pineapple", type: "new"}]

Answer 1

可以使用Array.prototype.reduce筛选出满足条件的项目

const 
  input = [
    { id: 1, name: "apple" },
    { id: 2, name: "mango" },
    { id: 3, name: "apple", type: "new" },
    { id: 4, name: "orange" },
    { id: 5, name: "orange", type: "new" },
    { id: 6, name: "pineapple", type: "new" },
  ],
  output = Object.values(
    input.reduce((r, o) => {
      if (!r[o.name] || (r[o.name].type === "new" && o.type !== "new")) {
        r[o.name] = o;
      }
      return r;
    }, {})
  );

console.log(output);

您也可以使用 Spread Syntax。

const 
  input = [
    { id: 1, name: "apple" },
    { id: 2, name: "mango" },
    { id: 3, name: "apple", type: "new" },
    { id: 4, name: "orange" },
    { id: 5, name: "orange", type: "new" },
    { id: 6, name: "pineapple", type: "new" },
  ],
  output = Object.values(
    input.reduce(
      (r, o) =>
        !r[o.name] || (r[o.name].type === "new" && o.type !== "new")
          ? { ...r, [o.name]: o }
          : r,
      {}
    )
  );

console.log(output);

Answer 2

您可以迭代数组并评估是否 'type: new' 并且尚不存在，然后弹出该项目。

let someArray = [{
    id: 1,
    name: "apple"
}, {
    id: 2,
    name: "mango"
}, {
    id: 3,
    name: "apple",
    type: "new"
}, {
    id: 4,
    name: "orange"
}, {
    id: 5,
    name: "orange",
    type: "new"
}, {
    id: 6,
    name: "pineapple",
    type: "new"
}];
console.info('Initial value:' + JSON.stringify(someArray));
someArray.forEach(function(item, index, object) {
    if (item.type === 'new' && someArray.filter(val => val.name === item.name && !val.type)) {
        object.splice(index, 1);
    }
});

console.info('Desired Result:' + JSON.stringify(someArray));

Answer 3

let someArray = [{id: 1, name:"apple"}, {id: 2, name:"mango"}, {id: 3, name:"apple", type: "new"}, {id: 4, name:"orange"}, {id: 5, name:"orange", type: "new"}, {id: 6, name: "pineapple", type: "new"}]
someArray.sort(function (a, b) {
  if (a.type !== 'undefined') return -1
  return 0
})
const result = someArray.reduce((resArr, currentArr) => {
  let other = resArr.some((ele) => currentArr.name === ele.name)
  if (!other) resArr.push(currentArr)
  return resArr
}, [])
console.log(result)

Answer 4

您可以使用 Map 按名称组合值，如果有两个值同名，只需使用不带 type = "new"

的值

let someArray = [{id: 3, name:"apple", type: "new"}, {id: 1, name:"apple"}, {id: 2, name:"mango"}, {id: 4, name:"orange"}, {id: 5, name:"orange", type: "new"}, {id: 6, name: "pineapple", type: "new"}]

function getUnique(arr){
  let mapObj = new Map()
  
  arr.forEach(v => {
    let prevValue = mapObj.get(v.name)
    if(!prevValue || prevValue.type === "new"){
      mapObj.set(v.name, v)
    } 
  })
  return [...mapObj.values()]
}

console.log(getUnique(someArray))

根据 JavaScript 中的属性值从对象数组中删除重复项

Remove duplicate from array of objects based on value of properties in JavaScript

javascript

arrays

ecmascript-6

array-reduce