Javascript | Set中的唯一对象 [英] Javascript | Unique object in Set

问题描述

如何阻止 Set 对象填充重复对象？

How can I prevent a Set object from being populated with duplicate objects?

  [    
    {
        prop1: [{value: "val", disabled: true}] (1)
        prop2: [{value: [4, 5], disabled: true}] (1)
        prop3: [{value: "someOtherValue", disabled: true}] (1)
    },

    {
        prop1: [{value: "val", disabled: true}] (1)
        prop2: [{value: [4, 5], disabled: true}] (1)
        prop3: [{value: "someOtherValue", disabled: true}] (1)
    },
    {
        prop1: [{value: "otherValue", disabled: true}] (1)
        prop2: [{value: [3], disabled: true}] (1)
        prop3: [{value: "", disabled: true}] (1)
    },
  ]

因此，当循环遍历数组时，我检查Set对象是否包含重复，但如果是，则检查一直返回false。

So while looping through the array I check if the Set object contains a duplicate, but event if it does, check returns false all the time.

let s = new Set();

//for loop starts here

let check = s.has(obj) // false

if(check == false){
    s.add(obj);
}

推荐答案

通过引用传递对象，这意味着当你将它们添加到集合中时，即使它们完全相同，如果用 === 进行检查，它们也不会相同。

Objects are passed by reference, which means that when you add them to a set, even if they are exactly the same, they will not be the same if you check them with ===.

var a = {val1: 'hello', val2: 'there'}
var b = {val1: 'hello', val2: 'there'}
console.log(a === b) // false
console.log(a == b)  // false

要解决此问题，您可以编写如下内容，取自这篇文章。

To solve this problem, you could write something like the following, taken from this article.

var a = {val1: 'hello', val2: 'there'};
var b = {val1: 'hello', val2: 'there'};

function isEquivalent(a, b) {
  // Create arrays of property names
  var aProps = Object.getOwnPropertyNames(a);
  var bProps = Object.getOwnPropertyNames(b);

  // If number of properties is different,
  // objects are not equivalent
  if (aProps.length != bProps.length) {
    return false;
  }

  for (var i = 0; i < aProps.length; i++) {
    var propName = aProps[i];

    // If values of same property are not equal,
    // objects are not equivalent
    if (a[propName] !== b[propName]) {
      return false;
    }
  }

  // If we made it this far, objects
  // are considered equivalent
  return true;
}

console.log(a === b); // false
console.log(a == b);  // false
console.log(isEquivalent(a, b)); // true

使用此算法将检查实际值对象而不是引用。

Using this algorithm will check the actual values of the objects rather than the references.

console.log(isEquivalent(a, b)) // true

这篇关于Javascript | Set中的唯一对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！