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

来点es6魔法怎么样?

obj.arr = obj.arr.filter((value, index, self) =>
  index === self.findIndex((t) => (
    t.place === value.place && t.name === value.name
  ))
)

参考URL

更通用的解决方案是:

const uniqueArray = obj.arr.filter((value, index) => {
  const _value = JSON.stringify(value);
  return index === obj.arr.findIndex(obj => {
    return JSON.stringify(obj) === _value;
  });
});

使用上述属性策略而不是JSON.stringify:

const isPropValuesEqual = (subject, target, propNames) =>
  propNames.every(propName => subject[propName] === target[propName]);

const getUniqueItemsByProperties = (items, propNames) => 
  items.filter((item, index, array) =>
    index === array.findIndex(foundItem => isPropValuesEqual(foundItem, item, propNames))
  );

如果希望propNames属性为数组或值,可以添加包装器:

const getUniqueItemsByProperties = (items, propNames) => {
  const propNamesArray = Array.from(propNames);

  return items.filter((item, index, array) =>
    index === array.findIndex(foundItem => isPropValuesEqual(foundItem, item, propNamesArray))
  );
};

允许getUniqueItemsByProperty('a')和getUniqueItemsByProperty(['a']);

Stackblitz示例

解释

首先了解使用的两种方法:过滤器,findIndex接下来,让你的想法让你的两个对象相等,并记住这一点。如果某个东西满足我们刚刚想到的标准,我们可以将其检测为复制品,但它的位置不在具有该标准的对象的第一个实例处。因此,我们可以使用上述标准来确定某个东西是否是重复的。

其他回答

function filterDuplicateQueries(queries){
    let uniqueQueries = [];
     queries.forEach((l, i)=>{
        let alreadyExist = false;
        if(uniqueQueries.length>0){
            uniqueQueries.forEach((k, j)=>{
                if(k.query == l.query){
                    alreadyExist = true;
                }
            });
        }
        if(!alreadyExist){
           uniqueQueries.push(l)
        }
    });

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。

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"
}]

这是我的解决方案,它基于object.prop搜索重复的对象,当找到重复的对象时,它会将array1中的值替换为array2值

function mergeSecondArrayIntoFirstArrayByProperty(array1, array2) {
    for (var i = 0; i < array2.length; i++) {
        var found = false;
        for (var j = 0; j < array1.length; j++) {
            if (array2[i].prop === array1[j].prop) { // if item exist in array1
                array1[j] = array2[i]; // replace it in array1 with array2 value
                found = true;
            }
        }
        if (!found) // if item in array2 not found in array1, add it to array1
            array1.push(array2[i]);

    }
    return array1;
}