Question

在一个数组中有一个可选数组，它具有对象键作为字符串，我想返回新数组中的所有字符串。

 this.arr =   [
      {
        text: "some text",
        numberValue: 560,
        booleanValue: true,
        arrayValue: [
          {
            text: "I am some text",
            numberValue: 13,
            booleanValue: false
          }
        ]
      },
      {
        text: "some",
        numberValue: 0,
        booleanValue: true,
        arrayValue: [
          {
            text: "I some text",
            numberValue: 12333,
            booleanValue: true
          }
        ]
      },
      {
        text: "someddkjd",
        numberValue: 0,
        booleanValue: true
      },
      {
        text: "someckckk",
        numberValue: 0,
        booleanValue: true,
        arrayValue: [
          {
            text: "Ime text",
            numberValue: 12333,
            booleanValue: true
          }
        ]
      }
]

我想返回一个以arrayValue的string属性为目标的字符串数组我想要的结果是

newArray = ["Iam some text", "I some text", "Ime text"];

我尝试的是

 for(let i = 0; i < this.arr.length; i++){
  this.stringArr.push(this.arr[i].arrayValue[i].text);
  }

该问题的其他几点： arrayValue是可选的，可以存在或不存在，就像是否看到对象number3没有arrayValue一样。另外，arrayValue内可以有多个对象

Answer 1

做类似的事情

this.stringArr = [];
for(let item of this.arr){
  for(let item2 of item.arrayValue){
    this.stringArr.push(item2.text);
  }
}

Answer 2

假设arrayValue数组中可以有许多个对象，那么您可以使用 Array.map 从中获取字符串。如果没有arrayValue属性，我们可以通过 Array.filter 过滤掉未定义的值。

const arr =  [{"text":"some text","numberValue":560,"booleanValue":true,"arrayValue":[{"text":"I am some text","numberValue":13,"booleanValue":false}]},{"text":"some","numberValue":0,"booleanValue":true,"arrayValue":[{"text":"I some text","numberValue":12333,"booleanValue":true}]},{"text":"someddkjd","numberValue":0,"booleanValue":true},{"text":"someckckk","numberValue":0,"booleanValue":true,"arrayValue":[{"text":"Ime text","numberValue":12333,"booleanValue":true}]}];
const newArray = arr.map(obj => obj.arrayValue && Array.isArray(obj.arrayValue) ? obj.arrayValue.map(ele => ele.text).join("") : undefined).filter(obj => obj);
console.log(newArray);

我们可以使用 Array.reduce 进行相同的操作，在逻辑中，我首先检查了属性是否存在，然后通过执行Array.isArray来检查属性是否确实是数组。是，然后在joined中对象的所有text属性上arrayValue：

const arr =  [{"text":"some text","numberValue":560,"booleanValue":true,"arrayValue":[{"text":"I am some text","numberValue":13,"booleanValue":false}]},{"text":"some","numberValue":0,"booleanValue":true,"arrayValue":[{"text":"I some text","numberValue":12333,"booleanValue":true}]},{"text":"someddkjd","numberValue":0,"booleanValue":true},{"text":"someckckk","numberValue":0,"booleanValue":true,"arrayValue":[{"text":"Ime text","numberValue":12333,"booleanValue":true}]}];
const newArray = arr.reduce((acc, ele) => ele.arrayValue && Array.isArray(ele.arrayValue) ? acc.concat(ele.arrayValue.map(ele => ele.text).join("")) : acc, []);
console.log(newArray);

我已经使用 Array.join() 来连接内部arrayValue对象的文本属性。

Answer 3

您可以像这样使用简单的 reduce 和 concat ：

const arr = [{text:"some text",numberValue:560,booleanValue:true,arrayValue:[{text:"I am some text",numberValue:13,booleanValue:false}]},{text:"some",numberValue:0,booleanValue:true,arrayValue:[{text:"I some text",numberValue:12333,booleanValue:true}]},{text:"someddkjd",numberValue:0,booleanValue:true},{text:"someckckk",numberValue:0,booleanValue:true,arrayValue:[{text:"Ime text",numberValue:12333,booleanValue:true}]}]

const texts = arr.reduce((r, { arrayValue }) => 
  arrayValue ? r.concat(arrayValue.map(a => a.text)) : r
, [])

console.log(texts)

从可选数组返回字符串数组

3 个答案: