Javascript 拼接去掉错误的元素

Question

我对这个非常简单的代码无法正常工作感到有些困惑：

 //find the index to be removed
 cardData.likeData.likeUids.forEach ((entry, index) => {
    if (entry === uid){
      uidFound = true
      uidIndex = index
      console.log ("Found uid, index is " + uidIndex)
      //console shows correct index
    }
  })
  let newLikeUids = cardData.likeData.likeUids.splice (uidIndex, 1)
  //instead of deleting the found index, the element before the index is removed... for some reason

知道为什么这不起作用吗？

Answer 1

你应该使用 findIndex。我不知道你的数组是什么样的，但在类似的情况下，你想从 1 和 0 的数组中删除第一个 1，你会写这样的东西：

const arr = [0,0,0,0,0,1,0,0,0];
arr.splice(arr.findIndex(e => e === 1), 1);
console.log(arr);

Answer 2

也许filter数组的方法可以帮到你

cardData.likeData.likeUids.filter ((entry) => {
    return entry !== uid;
});

如果您有很多 uid 需要删除

你可以试试

cardData.likeData.likeUids.filter ((entry) => {
    return uids.indexOf(entry) === -1;
});

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

Answer 3

我根据你写的做了一小段代码，似乎做了你想要的：

更改 UID 将决定从数据中删除什么。

let data = [1,2,3];

let uid = 1;
let foundUidIndex;

data.forEach ((entry, index) => {
    if (entry === uid){
      foundUidIndex = index;
      console.log ("Found uid, index is " + foundUidIndex)
    }
  })
 data.splice(foundUidIndex, 1);
  
console.log(data);

Answer 4

我注意到问题是您可能以错误的方式使用了 splice。

The splice() method changes the contents of an array by removing or replacing existing elements and/or adding new elements in place. To access part of an array without modifying it, see slice()

但是在您的代码中，您试图将 splice 的值分配给一个不起作用的值。

您可能混合了 slice 和 splice。我认为在这种情况下，您应该改用 slice。

The slice() method returns a shallow copy of a portion of an array into a new array object selected from start to end (end not included) where start and end represent the index of items in that array. The original array will not be modified.

Javascript 拼接去掉错误的元素

Javascript splice removes wrong element

javascript

arrays

splice