通过JavaScript中的类对象内的字典进行迭代

Question

I have a class:

    class Quizer {
        // construct new quiz for unique user
        constructor(quizObj) {
            this.quiz = quizObj;
            this.currentQuestionNum = 0;
            this.userSelections = [];
        }
        ...

    buttonAction(setup) {
        //var text = this.quiz.question1.question; <-- //works
        var text = this.quiz[currentQuestionNum].question; // doesnt work
    }
}

That is constructed here:

var quiz = new Quizer(questionObjects);

Where questionObjects is:

var questionObjects = {
    question1: {
        question: "Darwin explained his theory of evolution in a book called?",
        choices: [
            "this is the correct answer, choose me!",
            "On the Origin of Species",
            "Survival of the Fittest"
        ],
        correctAnswer: "On the Origin of Species"
    },

    question2: {
    ...
    }
}

In buttonAction, my goal is to iterate through questionObjects and get each question. Can someone help me with the syntax?

Answer 1

You need something like this

for(var key in questionObjects){
    // The following gives you the question for the current key
    questionsObjects[key].question
} 

As it is stated here :

The for...in statement iterates over the enumerable properties of an object, in arbitrary order. For each distinct property, statements can be executed.