在 Angular 中显示具有重复出现次数的唯一项目 尝试使用：

如何解决在 Angular 中显示具有重复出现次数的唯一项目 尝试使用：

我有一个像下面这样的对象数组：

ngOnInit(): void {
    this.bayService.selectedBay$.subscribe(
        p => {
            // do something with the Bay value
        }
    );

    this.bayService.invalidBay$.subscribe(
        p => {
            // do something with the invalidBay value
        }
    );
}

onSubmit(): void {
    this.bayService.selectedBayChanged(this.bayForm.get('bayStart').value);
}

ngOnDestroy(): void {
    // if you stored Subscription reference
    this.subscription.unsubscribe();
}

我想计算不同值的出现次数，例如，输出应该是这样的

var array =
[
    {"name":"user1","value":1}
    {"name":"user1","value":1}
    {"name":"user3","value":1}
]

我试过了：

var array =
[
    {"name":"user1","value":3}
    {"name":"user3","value":2}
]

但输出不是我想要的：

array.reduce((acc,o) => (acc[o.name] = (acc[o.name] || 0) + 1,acc),{})

解决方法

var array = [
              {"name":"user1","value":1},{"name":"user1",{"name":"user3","value":1}
            ]
    
    var reduced = array.reduce((acc,o) => (acc[o.name] = (acc[o.name] || 0) + 1,acc),{});
    
    //Method 1
    let result1 = [];
    for (var prop in reduced) {
      result1.push({name:prop,value:reduced[prop]});
    }
    
    console.log(result1)

    //Method 2
    var result2 = Object.keys(reduced).map(x =>  {
            return {name : x,value : reduced[x]}})   
            
    console.log(result2)

,

尝试使用：

var array = [
  { name: "user1",value: 1 },{ name: "user1",{ name: "user3",value: 1 }
];

function removeDuplicate(arr) {
  let thing = [];
  arr.map(x => {
    thing.push({
      name: x.name,value: array.filter(y => y.name == x.name).length
    });
    arr
      .filter(y => y.name == x.name)
      .map(y => {
        array.splice(array.findIndex(z => z.name == y.name),1);
      });
  });
  return thing;
}

console.log(removeDuplicate(array));

,

您可以使用以下代码，采用相同的代码，但使用Object keys() 方法进行了扩展

thingsWithDuplicates = [
    {"name":"user1","value":1}
]; 
 distinctThings = thingsWithDuplicates.reduce((acc,{});

 values = [];
 Object.keys(distinctThings).forEach(key => {
     values.push({'name': key,'value': distinctThings[key]}) 
 });
 console.log(values);