javascript - JS - 对象构造方法

Question

我正在尝试制作一个包含团队积分的对象(如下所示，其中显示“this.update”)。当我运行该程序时，它似乎没有给团队打分，甚至似乎没有评估两个团队的目标。

我希望 team1Points 和 team2Points 属性从 IF 语句派生，如上面的语句或其他解决方案会有所帮助，类似于两队平局得 1 分，赢得 3 分，输得得 0 分。

teamsArray = ["Blue Team", "Red Team"];

function match(team1Name, team2Name, team1Goals, team2Goals) {
  this.team1Name = team1Name;
  this.team1Goals = team1Goals;
  this.team2Name = team2Name;
  this.team2Goals = team2Goals;
  this.update = function() {
    if (team1Goals > team2Goals) {
      team1Points = 3;
      team2Points = 0;
    } else if (team2Goals > team1Goals) {
      team2Points = 3;
      team1Points = 0;
    } else if (team1Goals == team2Goals) {
      team1Points = 1;
      team2Points = 1;
    }
  };
  this.update();
}

testMatch();

function testMatch() {
  var match1 = new match(teamsArray[0], teamsArray[1], 2, 0);
  console.log(match1);
}

Answer 1

您的方法创建全局变量而不是属性，您甚至从未调用过它!

为了避免此类问题，我建议改用现代 JavaScript 语法。使用 'use strict'; 指令开始您的脚本以启用严格模式并使用 let 而不是 var 定义变量。如果这样做，浏览器将不允许您在函数内定义全局变量。

至于你的代码的解决方案:

function match(team1Name, team2Name, team1Goals, team2Goals) {
  this.team1Name = team1Name;
  this.team1Goals = team1Goals;
  this.team2Name = team2Name;
  this.team2Goals = team2Goals;
  this.team1Points = this.team2Points = 0;

  this.update = function() {
    if (this.team1Goals > this.team2Goals) {
      this.team1Points = 3;
      this.team2Points = 0;
    } else if (this.team2Goals > this.team1Goals) {
      this.team2Points = 3;
      this.team1Points = 0;
    } else if (this.team1Goals == this.team2Goals) {
      this.team1Points = 1;
      this.team2Points = 1;
    }
  };
}

并且不要忘记在某处调用 .update()。

m = new match("Alpha", "Beta", 0, 2);
m.update();

console.log("Team " + m.team1Name + " has " + m.team1Points + " points.");
console.log("Team " + m.team2Name + " has " + m.team2Points + " points.");