如何根据数组中的元素进行过滤？

Question

我有如下多个数组如下：

//Condition one
var categorys = [1, 2];

//useType = 0,Return useType=0 element

//useType = 1,Returns the same categorys element as c_id

var data = [
  {c_id:0, name:'phone', useType:0},
  {c_id:1, name: "milk", useType:1},
  {c_id:2, name: "apple", useType:1},
  {c_id:3, name: "orang", useType:1},
  {c_id:4, name: "red", useType:1}         
]

我做了以下尝试：

let result = data.filter((item, index) => {
  if(item.useType === 0) {
    return true
  } else if(item.useType === 1 && item.c_id === categorys[index]){
    return true
  }
  else {
    return false
  }
});

我想得到以下结果

[
  {c_id:0, name:'phone',useType:0},
  {c_id:1, name: "milk",useType:1},
  {c_id:2, name: "apple",useType:1}
]

但我只能得到一个

[
  {c_id:0, name:'phone',useType:0},
]

你能帮帮我吗？

Answer 1

您可以使用Array.prototype.includes() 来检查categories 数组是否包含特定的c_id 值：

const categories = [1, 2];

const data = [
  {c_id: 0, name: "phone", useType: 0},
  {c_id: 1, name: "milk", useType: 1},
  {c_id: 2, name: "apple", useType: 1},
  {c_id: 3, name: "orang", useType: 1},
  {c_id: 4, name: "red", useType: 1}         
];

const result = data.filter(({useType, c_id}) =>
    useType === 0 || useType === 1 && categories.includes(c_id));

console.log(result);

Answer 2

您可以使用.filter() 和.includes() 方法来获得所需的输出：

const categorys = [1, 2];

const data = [
  {c_id:0, name:'phone',useType:0},
  {c_id:1, name: "milk",useType:1},
  {c_id:2, name: "apple",useType:1},
  {c_id:3, name: "orang",useType:1},
  {c_id:4, name: "red",useType:1}         
];

const result = data.filter(
  ({ c_id, useType }) => ((useType == 0) || (useType == 1 && categorys.includes(c_id)))
);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 3

你需要使用includes:

let result = data.filter((item,index)=>{
    if(item.useType === 0){
       return true
    }else if(item.useType === 1 && categorys.includes(item.c_id)){
        return true
    }
    else{
       return false
    }
});

但为了避免对类别数组进行迭代，您可以将其设为这样的对象，从而提高性能：

var categories = {
  "1": true,
  "2": true
};

var data = [
  {c_id:0, name:'phone',useType:0},
  {c_id:1, name: "milk",useType:1},
  {c_id:2, name: "apple",useType:1},
  {c_id:3, name: "orang",useType:1},
  {c_id:4, name: "red",useType:1}         
]

let result = data.filter((item,index)=>{
    if(item.useType === 0){
       return true
    }
    
    if(item.useType === 1 && categories[item.c_id] === true){
        return true
    }
    
    return false
});

console.log(result);