角度加载file.json并转换为对象类

Question

My app load a file.json of users'pc:

app.component.html

  <div class="file btn btn-lg btn-primary"> Upload <input type="file" class="upload" (change)="changeListener($event.target.files)"> </div> 

In my app.component.ts

  user: User;
  userArray: Array<User>;
  fileList: Array<any>;

  ngOnInit() {
   this.user = new User();
   this.userArray= Array<User>();
   this.fileList= Array<any>();
  }

THEN the method that receive file:

  public changeListener(files: FileList) {
    if (files && files.length > 0) {
      let file: File = files.item(0);

      let reader: FileReader = new FileReader();
      reader.readAsText(file);
      reader.onload = (e) => {
        let loadFile: string = reader.result;
        JSON.stringify(loadFile)
        this.fileList = loadFile.split('\r\n');

    if (this.fileList.length > 0) {
      for (const i of this.fileList) {
        if (i !== null) {

          this.user = i; //--I THINK HERE IS MY PROBLEM--
          this.userArray.push(this.user); //----HERE IS UNDEFINED

          console.log('user - ', this.user); 
        } else {
          console.log('NULL');
        }
      }
        console.log('userArray - ', this.userArray.length); //---BUT HERE SHOW SIZE OF .JSON LOADED
      }
    }
  }

My question is: Like to convert 'i' in User object? Or fileList in user Array?

my user.class have same properties of json.file...I see a lot responses here but nothing works.

My json file is a list of:

{"DATE ":"22/04/2018","HOUR ":"03:00:55","YEAR ":2014,"NUM_TURN (*) ":1,"DESC_E (*) ":"Gerais 2014","SIGLA_UF ":"SE","SIGLA_UE (*) ":"SE", ...e more others 15 properties}

Answer 1

Aren't you using fileList instead of this.fileList ?

Anyway I would try to cast i :

this.user = i as User;

Answer 2

fileList是一个字符串数组，因此您需要将i （这是字符串类型，尽管在这种情况下为any ）转换为json对象：

this.user = JSON.parse(i);