Question

我正在构建一个视频保存服务作为项目，并拥有从数据库response.array[]获取的用户保存视频的数组，然后我将videoId推送到显示数组video[]但是在使用videoId显示相应的console.log()时，它仍然未定义。

我的代码段如下所示。

let video = [];
this.service.nextVideo().subscribe( response =>
{
    response.array.forEach(element => {
    video.push(element.videoId);
  });
})
console.log(video[0]); //Output is undefined

完整的代码段就像这样

nxtVideo(){
    let video = [];
    this.service.nextVideo().subscribe( response => 
    {
        response.array.forEach(element => {
          console.log(element.videoId);//Display's video id
          video.push(element.videoId);
        });
    })
    console.log(video[0]); //Output undefined
    console.log(video); //Output shows all elements but on accessing specific elements it shows undefined
    return (video[this.offset++]); //offset is a global variable to measure watched videos
  }

  Launch(){
    let videoId = this.nxtVideo();
    //The Display table starts here
  }

Answer 1

试试这段代码。它必须是有效的，因为它的异步功能。

let video = [];
this.service.nextVideo().subscribe( response =>
{
    response.array.forEach(element => {
       video.push(element.videoId);
    });
    console.log(video[0]); //Output is undefined
})

即使将元素推入其中，数组元素也未定义

1 个答案: