如何在打字稿/javascript中过滤数组以获取唯一ID [重复]

Question

我有一个对象数组，如何在 typescript/javascript 中过滤数组以获取唯一 ID

列表数组-

[{
    global_id: "269a8bded9bd4ecaa0e501c170a71f5a"
    icon: "/odb/icons/ip/ip_32.svg"
    id: "269a8bded9bd4ecaa0e501c170a71f5a"
}, {
    global_id: "269a8bded9bd4ecaa0e501c170a71f5a"
    icon: "/odb/icons/ip/ip_32.svg"
    id: "269a8bded9bd4ecaa0e501c170a71f5a"
}, {
    global_id: 348
    icon: "/odb/icons/ip/ip_32.svg"
    id: 348
}, {
    global_id: 201
    icon: "/odb/icons/ip/ip_32.svg"
    id: 201
}]

以此类推，

我想以不应该列出重复元素的方式过滤我的对象数组。

list.filter()如果可以的话我想用。

_.uniqBy(list, 'id'); 在 lodash 中可用，但我想使用 typescript/javascrpt .filter 方法。 请指导。

Answer 1

使用Array#reduce、Map 和spread operator

var data =[{global_id:"269a8bded9bd4ecaa0e501c170a71f5a",icon:"/odb/icons/ip/ip_32.svg",id:"269a8bded9bd4ecaa0e501c170a71f5a"},{global_id:"269a8bded9bd4ecaa0e501c170a71f5a",icon:"/odb/icons/ip/ip_32.svg",id:"269a8bded9bd4ecaa0e501c170a71f5a"},{global_id:348,icon:"/odb/icons/ip/ip_32.svg",id:348},{global_id:201,icon:"/odb/icons/ip/ip_32.svg",id:201}];

const res = [...data.reduce((a,c)=>{
  a.set(c.global_id, c);
  return a;
}, new Map()).values()];

console.log(res);

---

性能

function getRndInteger(min, max) {
  return Math.floor(Math.random() * (max - min)) + min;
}

const keys = [
  'a', 'b', 'c', 'd', 'e', 'f', 'g',
];

const generatedArray = [];

for (let i = 0; i < 100000; i += 1) {
  generatedArray.push({
    global_id: keys[getRndInteger(0, keys.length - 1)],
    val: i,
  });
}

const start = Date.now();

const unique = [...generatedArray.reduce((a,c)=>{
  a.set(c.global_id, c);
  return a;
}, new Map()).values()];

console.log(unique);

console.log(`It took ${Date.now() - start}ms to unique`);

Answer 2

这是一个使用 Array.filter 的解决方案

function uniqueArrayOfObject(array, keyToBeUnique) {
  // Filter by looking at the next objects if the key is present a second time
  return array.filter((x, xi) => !array.slice(xi + 1)
    .some(y => y[keyToBeUnique] === x[keyToBeUnique]));
}

function getRndInteger(min, max) {
  return Math.floor(Math.random() * (max - min)) + min;
}

const keys = [
  'a', 'b', 'c', 'd', 'e', 'f', 'g',
];

const generatedArray = [];

for (let i = 0; i < 100000; i += 1) {
  generatedArray.push({
    uniqueKey: keys[getRndInteger(0, keys.length - 1)],
    val: i,
  });
}

const start = Date.now();

const unique = uniqueArrayOfObject(generatedArray, 'uniqueKey');

console.log(unique);

console.log(`It took ${Date.now() - start}ms to unique`);

---

其他解决方案（更快）

function uniqueArrayOfObject(array, keyToBeUnique) {
  return Object.values(array.reduce((tmp, x) => {
    // You already get a value
    if (tmp[x[keyToBeUnique]]) return tmp;

    // You never envcountered this key
    tmp[x[keyToBeUnique]] = x;

    return tmp;
  }, {}));
}

function getRndInteger(min, max) {
  return Math.floor(Math.random() * (max - min)) + min;
}

const keys = [
  'a', 'b', 'c', 'd', 'e', 'f', 'g',
];

const generatedArray = [];

for (let i = 0; i < 100000; i += 1) {
  generatedArray.push({
    uniqueKey: keys[getRndInteger(0, keys.length - 1)],
    val: i,
  });
}

const start = Date.now();

const unique = uniqueArrayOfObject(generatedArray, 'uniqueKey');

console.log(unique);

console.log(`It took ${Date.now() - start}ms to unique`);