fetch data from the Json file use local variable as a key

Question

const quizData = [{
        question: "Which of the following purpose, JavaScript is designed for ?",
        a: 'To Execute Query Related to DB on Server',
        b: 'To Style HTML Pages',
        c: ' To Perform Server Side Scripting Opertion',
        d: ' To add interactivity to HTML Pages.',
        correct: 'd'
    },
    {
        question: "how old is adnan?",
        a: '10',
        b: '20',
        c: '30',
        d: '40',
        correct: 'c'
    }]

The above is a quiz data. I want to get only the value of key that is in key 'correct' value. Like in first question the correct answer is 'd' so I only want to get the value of key 'd'.

I tried this code but it gave undefined answer

let rs = quizData[0].correct

console.log(quizData[0].question + "\n" + quizData[0].rs)

As `rs` holds the key, you need to interpolate like this `console.log(quizData[0].question + "\n" + quizData[0][rs])` — chrisg86, May 10 '22 at 18:08
in rs the 'd' is saved, quizData[0].rs give undefined but i want the value of 'd' from quizData at 0 index — adnan sadiq, May 10 '22 at 18:11
i want to get only the question and the correct answer's value — adnan sadiq, May 10 '22 at 18:13

score 0 · Answer 1 · answered May 10 '22 at 18:09

0

You can use code like this:

function getCorrectAnswerAtIndex(data, index) {
  const item = data[index]
  return item[item.correct]
}

Usage:

// get answer at 0
console.log(quizData[0].question + '\n' + getCorrectAnswerAtIndex(0))

answered May 10 '22 at 18:09

Konrad

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score 0 · Answer 2 · answered May 10 '22 at 18:13

Looks like you're trying to figure out how to access an object's properties when the name of the property is stored in a variable (instead of hardcoded).

The follow 3 bits of code all get the same value out of myObj:

myObj.myKey

or

myObj['myKey']

or

const myDynamicKey = 'myKey';

myObj[myDynamicKey]

So the follow should work for you in this case:

const quizData = [{
    question: "Which of the following purpose, JavaScript is designed for ?",
    a: 'To Execute Query Related to DB on Server',
    b: 'To Style HTML Pages',
    c: ' To Perform Server Side Scripting Opertion',
    d: ' To add interactivity to HTML Pages.',
    correct: 'd'
}, {
    question: "how old is adnan?",
    a: '10',
    b: '20',
    c: '30',
    d: '40',
    correct: 'c'
}];

const correctLetter = quizData[0].correct;

console.log(quizData[0].question + "\n" + quizData[0][correctLetter]);

fetch data from the Json file use local variable as a key

2 Answers2