javascript - 如何在 javascript 中为 json 对象创建方法？

Question

我创建了一个测验，其中每个问题都是一个 Question 对象，该问题具有 print quiestion 等方法。我已将问题添加到 javascript 文件中，但我想将问题移至外部 Json 文件。

但是，我找不到任何文章介绍如何在这种情况下为导入的 Json 对象(问题对象)创建两种方法。下面是使用 getJson 之前使用一个方法获取测验对象的一段代码:

$(function(){

// <-- QUESTION OBJECT -->
function Question(question, choices, correctChoice, userAnswer, type) {

    this.question = question;
    this.choices = choices;
    this.correctChoice = correctChoice;
    this.userAnswer = userAnswer;
    this.type = type;   // either radio buttons or check boxes

    // <-- write question method -->
    this.writeQuestion = function() {

        var questionContent;
        questionContent = "<p class='question'>" + (currentQue + 1) + ". " +    this.question + "</p>";
        var checked = "";

        if(this.type === "radio") {

            for(var i=0; i < this.choices.length; i++) {

                if((i+1) == this.userAnswer)
                    checked = "checked='checked'";

                questionContent += "<p><input class='css-radio' id='radio" + (i+1) + "' " +  checked  + " type='radio' name='choices' value='choice'></input>";
                questionContent += "<label class='css-label' for='radio" + (i+1) + "'>" + this.choices[i] + "</label></p>"; 

                checked = "";
            }
        }

        else {

            for(var i=0; i < this.choices.length; i++) {

                if ((i+1) == this.userAnswer[i])
                    checked = "checked='checked'";

                questionContent += "<p><input class='css-checkbox' id='checkbox" + (i+1) + "' " +  checked  + " type='checkbox' name='choices' value='choice'></input>";
                questionContent += "<label class='css-label-checkbox' for='checkbox" + (i+1) + "'>" + this.choices[i] + "</label></p>";

                checked = "";
            }
        }

    return $quizContent.html(questionContent);
    };

Answer 1

您应该创建一个构造函数来接收 json 并使用您提供的 json 定义其中的所有方法，大致如下:

function Question(questionJson) {
    var data = questionJson;

    //Public "methods" are defined to "this"
    this.getCorrectAnswer = function() {
        return data.correctAnswer;
    };

    //Private "methods
    var doSomethingCrazy = function() {
        return "crazy";
    };

    this.getSomethingCrazy = function() {
        return doSomethingCrazy();
    };
}

然后，假设您有一系列问题:

var questions = [
    {questionId: '1', correctAnswer: 'a', possibleAnswers: []},
    {questionId: '2', correctAnswer: 'a', possibleAnswers: []},
];

你会:

var instances = [];
for (var q in questions) {
    instances[q.questionId] = new Question(q);
}