Javascript:如何将变量存储在构造函数中的空变量中

Question

在 startGame() 方法中，我尝试将 getRandomPhrase() 方法中选定的短语存储到 null 属性。它一直向我抛出一个错误，说

Game.activePhrase is null

我做错了什么？

游戏.js:

class Game {

  constructor() {
    this.missed = 0;
    //directly put the phrases in the constructor
    this.phrases = [new Phrase("hello world"),
      new Phrase("Wolf on wall street"),
      new Phrase("Despite making"),
      new Phrase("Karen took the kids"),
      new Phrase("alright about to head out")
    ];
    this.activePhrase = null;
  }

  getRandomPhrase() {
    //returns 5 of the random phrases
    return this.phrases[Math.floor(Math.random() * this.phrases.length)];
  }

  startGame() {
    let hid = document.getElementById('overlay');
    hid.style.display = "none";
    let phrs = this.getRandomPhrase();
    phrs.addPhraseToDisplay();
    return this.activePhrase(phrs); //trying to store it by doing this
  }
}

App.js

const game = new Game();
game.startGame();
console.log(`Active Phrase - phrase: ${game.activePhrase.phrase}`);

Answer 1

在从 startGame 方法返回之前为 activePhase 变量赋值

this.activePhrase = phrs;

喜欢

  startGame() {
    let hid = document.getElementById('overlay');
    hid.style.display = "none";
    let phrs = this.getRandomPhrase();
    phrs.addPhraseToDisplay();
    this.activePhrase = phrs; //Key to fix your issue
    return this.activePhrase;
  }