JavaScript函数语法错误混淆

Question

我不知道这段代码有什么问题

class CatMusicPlayer {

  constructor(url,playPauseBtn,progressbar,progressTime,durationTime) {
    this.url = url;
    this.playPauseBtn = playPauseBtn;
    this.progressbar = progressbar;
    this.progressTime = progressTime;
    this.durationTime = durationTime;
    const _thisMP = this;

    new Media(url,null,this.logerror,function(mediaStatus){
       _thisMP.progressbar(); // call here

        /*
            i want to use this.progressbar,
            but in this block "this" reffers to Media class.
            Media is kind of another class similar to CatMusicPlayer
        */

    });
  }

这给出了语法错误，但我认为语法是正确的。有人可以帮忙吗？ 谢谢。

Answer 1

由于automatic semicolon insertation (ASI)，您将返回undefined。

return                            // colon is inserted here
     {                            // never reached
         job1: task1,
         job2: task2
     };

您可以将括号移动到return语句的行中。

return {
         job1: task1,
         job2: task2
     };