Learning Javascript. I'm stuck!

[fabiankong8]

I’m trying to push an array into another. However it is not working.

var input = require('readline-sync');

class MCQ {
    constructor(question, choices, answer, category) {
        this.question = question;
        this.choices = choices;
        this.answer = parseInt(answer);
        this.category = parseInt(category);
    }
}//MCQ


class Quiz {
    constructor() {
        this.questionPool = []; //declare the question pool property of the quiz class
        this.mcqSelected = [];

        //populate 5mcqs and push them into array
        this.questionPool.push(new MCQ("A pull or a push applied or exerted on an object is", ["Energy", "Force", "Velocity", "Distance"], 1, 1));
        this.questionPool.push(new MCQ("What is the unit of force?", ["Degree", "Joule", "Newton", "Pascal"], 2, 1));
        this.questionPool.push(new MCQ("What is defined as mass times the distance.", ["Velocity", "Work", "Energy", "Temperature"], 1, 1));
        this.questionPool.push(new MCQ("When an object is in motion, what kind of energy does it possess?", ["Kinetic Energy", "Potential Energy", "Electrical Energy", "Chemical Energy"], 0, 1));
        this.questionPool.push(new MCQ("What is the force that holds back a motion", ["Gravity", "Friction", "Momentum", "Mass"], 1, 1));

        this.questionPool.push(new MCQ("A", ["Energy", "Force", "Velocity", "Distance"], 1, 2));
        this.questionPool.push(new MCQ("B?", ["Degree", "Joule", "Newton", "Pascal"], 2, 2));
        this.questionPool.push(new MCQ("C.", ["Velocity", "Work", "Energy", "Temperature"], 1, 2));
        this.questionPool.push(new MCQ("D?", ["Kinetic Energy", "Potential Energy", "Electrical Energy", "Chemical Energy"], 0, 2));
        this.questionPool.push(new MCQ("E", ["Gravity", "Friction", "Momentum", "Mass"], 1, 2));

        this.questionPool.push(new MCQ("1", ["Energy", "Force", "Velocity", "Distance"], 1, 3));
        this.questionPool.push(new MCQ("2?", ["Degree", "Joule", "Newton", "Pascal"], 2, 3));
        this.questionPool.push(new MCQ("3", ["Velocity", "Work", "Energy", "Temperature"], 1, 3));
        this.questionPool.push(new MCQ("4", ["Kinetic Energy", "Potential Energy", "Electrical Energy", "Chemical Energy"], 0, 3));
        this.questionPool.push(new MCQ("5", ["Gravity", "Friction", "Momentum", "Mass"], 1, 3));

        this.questionPool.push(new MCQ("6", ["Energy", "Force", "Velocity", "Distance"], 1, 4));
        this.questionPool.push(new MCQ("7", ["Degree", "Joule", "Newton", "Pascal"], 2, 4));
        this.questionPool.push(new MCQ("8", ["Velocity", "Work", "Energy", "Temperature"], 1, 4));
        this.questionPool.push(new MCQ("9", ["Kinetic Energy", "Potential Energy", "Electrical Energy", "Chemical Energy"], 0, 4));
        this.questionPool.push(new MCQ("10", ["Gravity", "Friction", "Momentum", "Mass"], 1, 4));


    }// constructor

    getNumberOfQuestion() {
        return this.questionPool.length;
    }

    // getQuestionAt(index) {
    //     return this.questionPool[index];
    // }


    pushSelectedQuestion() {
        for (var i = 0; i < this.getNumberOfQuestion; i++) {
            if (usercategory == this.questionPool[i].category) {
                this.mcqSelected.push(this.questionPool[i])
                return this.pushSelectedQuestion;
            }
        }

    }

}//Quiz

//------- main ----------------
var quiz = new Quiz();

function getName() {
    console.log("-= Welcome to Quiz Application =-");
    var name = input.question("please enter your name: ");
    var usercategory = parseInt(input.question("Hi " + name + ", please choose the quiz category you would like to attempt:" + "\n" + "\n" + "(1) Physic\n" + "(2) Chemistry\n" + "(3) History\n" + "(4) Geography\n" + ">> "));
    switch (usercategory) {
        case 1:
            console.log("The category you have selected is Physic")
            break;
        case 2:
            console.log("The category you have selected is Chemistry")
            break;
        case 3:
            console.log("The category you have selected is History")
            break;
        case 4:
            console.log("The category you have selected is Geography")
            break;

        default:
            break;
    }
}
function showquestion() {
    for (i = 0; i < 5; i++) {
        console.log(quiz.mcqSelected)
    }
}


getName();
quiz.pushSelectedQuestion();
// for (var i = 0; i < 5; i++) {
//     console.log(quiz.mcqSelected[i]);
// }
// console.log(quiz.mcqSelected);  // theres nothing inside the array

showquestion();
// console.log(questionSelected)
// showquestion();

I’m trying to get the selected category. Lets say physics, which is 1. I’m trying to push them from question.pool array to mcqselected array. However not sure where im wrong

[m_hutley]

@fabiankong8

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

getNumberOfQuestion is a method, not a property. You’ll need to call it instead of using it. i < this.getNumberOfQuestion()