是否可以在 JavaScript 的对象声明中执行循环

Question

我正在创建一个包含多项选择题的测验。问题和答案是从外部 xml 文件加载的。答案选项的数量并不一致。它可以变化。我正在从 xml 文件加载数据并将其转换为测验应用程序可以访问的全局 JSON 对象。有没有办法遍历 answers 对象声明中的答案？整个对象当前看起来像这样（注意currentQuestion 是对正在读取的 xml 的变量引用）：

var questionAnswerContentObject = {
    question: {
      questionTitle: currentQuestion.find("questionTitle").text(),
      questionBody: currentQuestion.find("questionBody").text()
    },
    answers: {
      // this is where the answers are supposed to go. 
      // the loop is just dummy test code. it fails with "Parsing error: Unexpected token ("
      for(var i=0;i<10;i++) {
        answer: i;
      }
    }
  };

Answer 1

您可以在使用数组初始化对象后添加其他答案。然后，您可以在阅读 XML 文件后使用 for 循环动态添加答案。您的对象可以设置为：

answer : {
    [
        answer1: {
        }
        ...
    ]
}

Answer 2

有没有办法遍历答案对象声明中的答案？

不，你不能

---

您可以做的是创建一个函数并初始化这些属性。

• 要初始化属性答案，您可以使用IIFE 设置必要的答案数组。

var questionAnswerContentObject = function() {
  this.question = {
    questionTitle: "title",
    questionBody: "body"
  };

  this.answers = (function() {
    // this is where the answers are supposed to go. 
    // the loop is just dummy test code. it fails with "Parsing error: Unexpected token ("
    var array = [];
    for (var i = 0; i < 10; i++) {
      array.push(i);
    }
    
    return array;
  })();
};

var questionObject = new questionAnswerContentObject()
console.log(questionObject);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 3

你可以这样做。

 var questionAnswerContentObject  = {};

questionAnswerContentObject.question.questionTitle = currentQuestion.find("questionTitle").text();

questionAnswerContentObject.answer = [];
for(var i=0;i<10;i++) {
 var ans = currentQuestion.find(i).text();
questionAnswerContentObject.answer.push(ans);
}

Answer 4

我认为您可以直接执行此操作，只要您可以访问原始项目的答案列表。您不能直接在对象文字内使用 for-loop。但您可以使用map 语句。

所以我想象这样一种场景，您可以通过数组访问答案，类似于您获得标题 (currentQuestion.find("questionTitle").text()) 的方式，也许是 currentQuestion.find("questionAnswers").values()。然后你可以简单地map 覆盖你文字中的结果：

// This is just a dummy implementation.  Don't know what the real one would look like
const currentQuestion = {
  questionTitle: 'Why?',
  questionBody: 'What is the meaning of life?',
  questionAnswers: ['Love', '42', 'Mu'],
  find: (prop) => ({text: _ => currentQuestion[prop],
                    values: _=> currentQuestion[prop]})
}

const questionAnswerContentObject = {
    question: {
      questionTitle: currentQuestion.find("questionTitle").text(),
      questionBody: currentQuestion.find("questionBody").text()
    },
    answers: currentQuestion.find("questionAnswers").values().map(i => ({answer: i}))
};

console.log(questionAnswerContentObject)

Answer 5

试试这个脚本。希望对你有帮助。

var quiz = {
        question1:"what is a function ?",
        question2:"what is polymorphysm ",
        question3:"List two javascript framework",
        question4:"what php is used for?",
        question5:"is Java multy threaded ?",
        quiz1:["to make code better","to arrange your program","a function is a reusable block  of code which you can use  in your program"],
        quiz2 :["to format your code","it is not necessary in programming","in objet oriented programming polymorphysim is the ability of an object to take on many form..."],
        quiz3:["django ,express","symphony ,ruby on rail"," jquery , angular"],
        quiz4:["doing some front programming","a program language to computer operating system ","php is used to built web site and interact with database..."],
        quiz5:["no because it improve complexity","yes , each thread cannot run code concurrently","yes in multy threaded program each can handle different task at the same time"],
        displayQuiz: (question)=>{

            switch(question){
                case "question1": console.log("Q1 : " + quiz.question1);
                    for (i=0 ; i< quiz.quiz1.length ;i++){  console.log( (i +1) + ") "+ quiz.quiz1[i]);} 
                    break;
                case "question2":  console.log("Q2 : " + quiz.question2);
                    for (i=0 ; i< quiz.quiz1.length ;i++){  console.log( (i +1) + ") "+ quiz.quiz2[i]);} 
                    break;
                case "question3": console.log("Q3 : " +quiz.question3);
                    for (i=0 ; i< quiz.quiz1.length ;i++){  console.log( (i +1) + ") "+ quiz.quiz3[i]);} 
                    break;
                case "question4": console.log("Q4 : " +quiz.question4);
                    for (i=0 ; i< quiz.quiz1.length ;i++){  console.log( (i +1) + ") "+ quiz.quiz4[i]);} 
                    break;
                case "question5": console.log("Q5 : " +quiz.question5);
                    for (i=0 ; i< quiz.quiz1.length ;i++){  console.log( (i +1) + ") "+ quiz.quiz5[i]);} 
                    break;
            }
        },
        findAnswer:(question)=>{

            switch(question){
                case "question1":  console.log( quiz.question1);
                    console.log("a function is a reusable block  of code which you can in your program ");
                    break;
                case "question2": console.log( quiz.question2); 
                    console.log("in objet oriented programming polymorphysim is the ability of an object to take on many form...");
                    break;
                case "question3": console.log(quiz.question3);
                    console.log(" jquery, angular...");
                    break;
                case "question4": console.log(quiz.question4);
                    console.log("php is used to built web site and interact with database...");
                    break;
                case "question5": console.log(quiz.question5);
                    console.log("yes in multy threaded program each can handle different task at the same time");
                    break;
            }
        }
    }

要显示问题 1 的测验问题：quiz.displayQuiz("question1")

找到正确答案：quiz.findAnswer("question1")

注意：不要忘记通知我潜在的错误。要在控制台上运行