Matching Elements From Two Arrays In Javascript

I am trying to make a small random quizz generator, first array has the questions and they are randomly displayed (when page is loaded or when page is refreshed), the second array

Solution 1:

Right now you have two lists. One contains questions, the other answers:

var questions = [ "2 + 2", "2 + 1", "1 + 1" ];
var answers = [ "4", "3", "2" ];

In order to easily check your user input, it's a good idea to convert this data structure to an object in which the question is the key, and the answer the value.

_{Note that this requires your question and answer combinations to be unique. I.e.: a question can not have multiple answers}

var questionsWithAnswers = {
  "2 + 2": "4",
  // etc.
}

You can convert the data in javascript, so you don't have to rewrite the lists:

var questionsWithAnswers = {};
for (let i = 0; i < questions.length; i += 1) {
  questionsWithAnswers[question[i]] = answers[i];
}

Now, your check for a question is:

var answerIsCorrect = questionsWithAnswers[question] === userInput;

Solution 2:

First of all, you do understand that having a question and answer available in JS is not a good idea, cause user can see the code.

Anyway, I would combine questions and answer into one structure.

var QAs = [["How many sides has a hexagon", "6"],
    ["A circle has...degrees?", "360"]]; // and so onlet randomItem = QAs[Math.floor(Math.random()*myQs.length)];

document.getElementById("demo").innerHTML = randomItem[0];

functionuserAnswer() {
    const check = document.getElementById('answer').value;
    if (check == randomItem[1]) {  // check randomItem availability in this scope. otherwise save to to window.randowItem scope.
        sayMessage = check + "  is the correct answer!";
    } else {
        sayMessage = check + "  is not the correct answer....";
    }
    document.getElementById("userA").innerHTML = sayMessage;
}

Solution 3:

I'd recommend revising the schema of your questions.

Housing questions and answers together within objects would probably be the least error prone approach.

See below for a practical example.

// Questions.const questions = [
  {q: 'How may sidea has a hexagon', a: 6},
  {q: 'A circle has...degrees?', a: 360},
  {q: '2^3=...?', a: 8},
  {q: '2+2:2=..?', a: 3},
  {q: 'A triangle has....degrees?', a: 180},
  {q: 'Square root of 2 is...?', a: 1.41}
]

// Selected.const selected = questions[Math.floor(Math.random()*questions.length)]

// Question.const question = selected.qdocument.getElementById('question').innerHTML = question

// Normalise.constnormalise = (number) => Math.round(parseFloat(number), 2)

// Submit Answer.document.getElementById('form').addEventListener('submit', (event) => {
  event.preventDefault()
  const userAnswer = normalise(document.getElementById('answer').value)
  const actualAnswer = normalise(selected.a)
  const isCorrect = (userAnswer == actualAnswer)
  document.getElementById('feedback').innerHTML = isCorrect && 'Correct 👍' || 'Incorrect 👎'
})

<div><pid="question"></p></div><formid="form"><div><inputid="answer"placeholder="Answer .."/></div><button>Submit answer</button></form><div><pid="feedback"></p><div>