在 JavaScript 中检查两个数组中的重复元素 [重复]

Question

我有两个数组，我希望将这两个组合起来，重复项不会亮起，只添加新项，我在控制台中看到组合数组 我还想在控制台的列表中查看重复项 我的意思是，我需要两个输出，一个告诉我重复是什么，一个告诉我一个新的数组，该数组由两个没有重复的数组组合而成。 我写了这段代码，但它不能正常工作 谢谢你指导我

预期输出：

newContact : [
  {
    "id": 1,
    "name": "Oliver"
  },
  {
    "id": 2,
    "name": "Liam"
  }
   {
    "id": 3,
    "name": "James"
  }
   {
    "id": 4,
    "name": "Lucas"
  }
]
duplicateContacts: Oliver

let array1 = [
  { id: 1, name: "Oliver" },
  { id: 2, name: "Liam" },
];
let array2 = [
  { id: 1, name: "Oliver" },
  { id: 3, name: "James" },
  { id: 4, name: "Lucas" },
];
let newContact = array1.filter((item) => item.id !== array2.id);
console.log("newContact :", newContact);
console.log("duplicateContacts:");

Answer 1

猜测重复表示相同的id，将数组条目添加到映射以查找重复项，并且映射包含唯一项

const array1 = [
  { id: 1, name: "Oliver" },
  { id: 2, name: "Liam" },
];
const array2 = [
  { id: 1, name: "Oliver" },
  { id: 3, name: "James" },
  { id: 4, name: "Lucas" },
];

const duplicates = [];
const map = new Map();

const fill = (array) => array.forEach(item => {
  if (map.has(item.id)) {
    duplicates.push(item);
  } else {
    map.set(item.id, item);
  }
});

fill(array1);
fill(array2);

console.log(duplicates);
console.log([...map.values()]);

编辑

要将数组作为输入，请创建一个函数

const inspect = (...arrays) => {
    const duplicates = [];
    const map = new Map();

    const fill = (array) => array.forEach(item => {
      if (map.has(item.id)) {
        duplicates.push(item);
      } else {
        map.set(item.id, item);
      }
    });

    arrays.forEach(array => fill(array));

    console.log(duplicates);
    console.log([...map.values()]);
};


const array1 = [
  { id: 1, name: "Oliver" },
  { id: 2, name: "Liam" },
];
const array2 = [
  { id: 1, name: "Oliver" },
  { id: 3, name: "James" },
  { id: 4, name: "Lucas" },
];

inspect(array1, array2);

Answer 2

您可以从 array2 和所有 id 中获取 Set 并过滤另一个数组。

const
    array1 = [{ id: 1, name: "Oliver" }, { id: 2, name: "Liam" }],
    array2 = [{ id: 1, name: "Oliver" }, { id: 3, name: "James" }, { id: 4, name: "Lucas" }],
    set2 = new Set(array2.map(({ id }) => id)),
    duplicateContacts = array1.filter(({ id }) => set2.has(id));
    allContacts = [...array1, ...array2].filter(
        (s => ({ id }) => !s.has(id) && s.add(id))
        (new Set)
    ),

console.log("allContacts:", allContacts);
console.log("duplicateContacts:", duplicateContacts);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 3

三种方法：

• filter 获取重复元素数组

• map 只恢复一列的数组

• some 描述如何比较数组中的对象

   const duplicates = array1.filter(value => array2.some(oneElement => oneElement.id === value.id));
  const duplicatesId = array1.filter(value => array2.some(oneElement => oneElement.id === value.id)).map(oneElement => oneElement.id);
  
  
  const mergedArray = [ 
   ...array1, 
   ...array2.filter(value => !duplicatesId.some(oneDuplicate => oneDuplicate === value.id))
  ];
  

const array1 = [
  { id: 1, name: "Oliver" },
  { id: 2, name: "Liam" },
];

const array2 = [
  { id: 1, name: "Oliver" },
  { id: 3, name: "James" },
  { id: 4, name: "Lucas" },
];

const duplicates = array1.filter(value => array2.some(oneElement => oneElement.id === value.id));
const duplicatesId = array1.filter(value => array2.some(oneElement => oneElement.id === value.id)).map(oneElement => oneElement.id);


const mergedArray = [ 
  ...array1, 
  ...array2.filter(value => !duplicatesId.some(oneDuplicate => oneDuplicate === value.id))
];

console.log(duplicates);
console.log(duplicatesId);
console.log(mergedArray);