我收到未捕获的TypeError错误？

Question

I am creating a simple quiz app but I am stuck at making an object constructor the error is Uncaught TypeError: Question.pushQuestion is not a function

function Question(question){
    this.question = [];
}

Question.prototype.pushQuestion = function(question){
    this.question.push(question);
}

var question1 = Question("is 1 = 1 ?");
Question.pushQuestion(question1);//error

Answer 1

var question1 = new Question("is 1 = 1 ?");

You've missed the new keyword.

Also, here you create instance of your object:

var question1 = Question("is 1 = 1 ?");

So, you should use question1 in order to access any method from prototype chain, eg

question1.pushQuestion('How are you doing?');

Answer 2

When you define a function on an object prototype, you can invoke it by calling the function on a new-ed up instance of that object.

function Question(question){
    this.question = [];
}

Question.prototype.pushQuestion = function(question){
    this.question.push(question);
}

var question1 = new Question("is 1 = 1 ?");
question1.pushQuestion(question1);

What are you trying to achieve? Because I'm pretty sure you don't want to push the question itself into question.list .

Answer 3

It looks like you're trying to generate a list of questions. I would approach like this:

function QuestionList() {
    this.questions = [];
    this.counter = 0;
}

QuestionList.prototype.pushQuestion = function (question) {
    this.questions.push(question);
}

var questionList = new QuestionList();

questionList.pushQuestion("is 1 = 1 ?");
questionList.pushQuestion("is 1 = 2 ?");

questionList.questions // [ "is 1 = 1 ?", "is 1 = 2 ?" ]

You can then write a new method to get the next question in the list:

QuestionList.prototype.getNextQuestion = function (question) {
    return this.questions[this.counter++];
}

questionList.getNextQuestion(); // "is 1 = 1 ?"
questionList.getNextQuestion(); // "is 1 = 2 ?"

DEMO