Question

我正在尝试编写一个接受对象数组的函数，只选择对象中的特定键，并仅将该数组的唯一值返回到新的“已过滤”数组中。我正在尝试使用Array.filter并不断收到我的过滤数组未定义的错误。我哪里出错了？

const findUniques = function(arr) {


let rawArray = arr.map(res => res.id);

let filtered = rawArray.filter((id) => {
    return filtered.indexOf(id) === -1;
});
console.log(filtered)


};

这是我过滤的数组的模拟。

1630489261, 1630489261, 1630489261, 1630489313, 1630489313, 1630489261, 1630489313, 1707502836, 1590711681, 1588295455, 1630489313, 1707502836, 1588295455, 1707502836, 1590711681, 1707502836, 1707502836, 1707502836, 1707502836, 1707502836, 1588295455, 1588295455

如果我将过滤器设置为全局变量，则会被填充，但不会被过滤。 I.E.过滤了rawArray中的所有内容。

Answer 1

使用Array#filter

＆＃13;

rawArray = [1, 2, 3, 2, 3, 1, 4];

filtered = rawArray.filter((e, i) => rawArray.indexOf(e) === i);
    
console.log(filtered);

＆＃13;

使用Array#reduce

＆＃13;

let rawArray = [1, 2, 3, 2, 3, 1, 4],
filtered = rawArray.reduce(function (acc, item) {
    if (!acc.includes(item)){
        acc.push(item);
    }
    return acc; 
}, []);
console.log(filtered);

＆＃13;

Answer 2

const values = [1630489261, 1630489261, 1630489261, 1630489313, 1630489313, 1630489261, 1630489313, 1707502836, 1590711681, 1588295455, 1630489313, 1707502836, 1588295455, 1707502836, 1590711681, 1707502836, 1707502836, 1707502836, 1707502836, 1707502836, 1588295455, 1588295455];


function unique(array) {
  return array.reduce((a,b) => {
    let isIn = a.find(element => {
        return element === b;
    });
    if(!isIn){
      a.push(b);
    }
    return a;
  },[]);
}

let ret = unique(values);

console.log(ret);

https://jsfiddle.net/26bwknzf/4/

无法仅过滤数组的唯一值

2 个答案: