我有一个包含对象数组的对象。

obj = {};

obj.arr = new Array();

obj.arr.push({place:"here",name:"stuff"});
obj.arr.push({place:"there",name:"morestuff"});
obj.arr.push({place:"there",name:"morestuff"});

我想知道从数组中删除重复对象的最佳方法是什么。例如,obj.arr将变成。。。

{place:"here",name:"stuff"},
{place:"there",name:"morestuff"}

当前回答

const uniqueElements = (arr, fn) => arr.reduce((acc, v) => {
    if (!acc.some(x => fn(v, x))) { acc.push(v); }
    return acc;
}, []);

const stuff = [
    {place:"here",name:"stuff"},
    {place:"there",name:"morestuff"},
    {place:"there",name:"morestuff"},
];

const unique = uniqueElements(stuff, (a,b) => a.place === b.place && a.name === b.name );
//console.log( unique );

[{
    "place": "here",
    "name": "stuff"
  },
  {
    "place": "there",
    "name": "morestuff"
}]

其他回答

如果不想指定财产列表:

function removeDuplicates(myArr) {
  var props = Object.keys(myArr[0])
  return myArr.filter((item, index, self) =>
    index === self.findIndex((t) => (
      props.every(prop => {
        return t[prop] === item[prop]
      })
    ))
  )
}

再见!与IE11不兼容。

如果数组包含对象,则可以使用此方法删除重复的

const persons= [
      { id: 1, name: 'John',phone:'23' },
      { id: 2, name: 'Jane',phone:'23'},
      { id: 1, name: 'Johnny',phone:'56' },
      { id: 4, name: 'Alice',phone:'67' },
    ];
const unique = [...new Map(persons.map((m) => [m.id, m])).values()];

如果删除基于电话的重复项,只需将m.id替换为m.phone

const unique = [...new Map(persons.map((m) => [m.phone, m])).values()];

我有一个完全相同的要求,即基于单个字段上的重复项删除数组中的重复对象。我在这里找到了代码:Javascript:从对象数组中删除重复项

所以在我的示例中,我要从数组中删除具有重复licenseNum字符串值的任何对象。

var arrayWithDuplicates = [
    {"type":"LICENSE", "licenseNum": "12345", state:"NV"},
    {"type":"LICENSE", "licenseNum": "A7846", state:"CA"},
    {"type":"LICENSE", "licenseNum": "12345", state:"OR"},
    {"type":"LICENSE", "licenseNum": "10849", state:"CA"},
    {"type":"LICENSE", "licenseNum": "B7037", state:"WA"},
    {"type":"LICENSE", "licenseNum": "12345", state:"NM"}
];

function removeDuplicates(originalArray, prop) {
     var newArray = [];
     var lookupObject  = {};

     for(var i in originalArray) {
        lookupObject[originalArray[i][prop]] = originalArray[i];
     }

     for(i in lookupObject) {
         newArray.push(lookupObject[i]);
     }
      return newArray;
 }

var uniqueArray = removeDuplicates(arrayWithDuplicates, "licenseNum");
console.log("uniqueArray is: " + JSON.stringify(uniqueArray));

结果:

uniqueArray是:

[{"type":"LICENSE","licenseNum":"10849","state":"CA"},
{"type":"LICENSE","licenseNum":"12345","state":"NM"},
{"type":"LICENSE","licenseNum":"A7846","state":"CA"},
{"type":"LICENSE","licenseNum":"B7037","state":"WA"}]

这里是ES6的解决方案,您只想保留最后一项。该解决方案功能强大,符合Airbnb风格。

const things = {
  thing: [
    { place: 'here', name: 'stuff' },
    { place: 'there', name: 'morestuff1' },
    { place: 'there', name: 'morestuff2' }, 
  ],
};

const removeDuplicates = (array, key) => {
  return array.reduce((arr, item) => {
    const removed = arr.filter(i => i[key] !== item[key]);
    return [...removed, item];
  }, []);
};

console.log(removeDuplicates(things.thing, 'place'));
// > [{ place: 'here', name: 'stuff' }, { place: 'there', name: 'morestuff2' }]

如果您只需要通过对象的一个字段进行比较,则可以使用Array迭代方法执行此操作:

    function uniq(a, param){
        return a.filter(function(item, pos, array){
            return array.map(function(mapItem){ return mapItem[param]; }).indexOf(item[param]) === pos;
        })
    }

    uniq(things.thing, 'place');