JavaScript Questions

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1. What's the index of specific character?

"BOOMIN".indexOf("O");

• A: 2
• B: 1
• C: 3
• D: -1

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2. What's the output?

let friendsAtParty = 20;
while (friendsAtParty > 10) {
  friendsAtParty = friendsAtParty + 1;
}
console.log(friendsAtParty);

• A: true
• B: false
• C: Infinite
• D: undefined

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3. What's the output?

"BOOMIN".indexOf("o"); // Here `o` is small.

• A: 2
• B: 1
• C: 3
• D: -1

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4. What's the output?

let answerToLife = 4 + 1 * 2 * 4 + 2;
console.log(answerToLife);

• A: 42
• B: 14
• C: 16
• D: 40

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5. What's the output?

let boomin = [100, 50, 2].sort();
console.log(boomin);

• A: [2, 50, 100]
• B: [100, 50, 2]
• C: [100, 2, 50]
• D: [2, 100, 50]

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6. What's the output?

let abc = "abc";
abc[1] = "d";
console.log(abc);

• A: "d"
• B: "abc"
• C: "adc"
• D: error

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7. What's the output?

let boomin = [1, 2, 3];
result = boomin.concat(4);
console.log(boomin);

• A: [1,2,3]
• B: [1,2,3,4]
• C: 4
• D: [1,2,3,[4]]

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8. Which one is a non-primitive data type?

• A: boolean
• B: Array
• C: String
• D: Number

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9. What's the output?

function getAge(...args) {
  console.log(typeof args);
}

getAge(21);

• A: "number"
• B: "array"
• C: "object"
• D: "NaN"

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10. String in Javascript are editable value?

• A: true
• B: false

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11. What's the output?

function doesThisWork("Boomin") {
  return true
}

• A: true
• B: undefined
• C: SyntaxError
• D: false