ES6+ Features interview questions

18 real ES6+ Features questions from the JavaScript bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.

1. What is Destructuring?

Junior
  1. A.a ...args parameter that gathers remaining arguments into a real array
  2. B.syntax to unpack array elements or object properties into distinct variables
  3. C.the ?? operator that returns its right operand only when the left is null or undefined (unlike || which also triggers on any falsy value)
  4. D.function parameter values used when the corresponding argument is undefined
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3. Which statement is correct?

Junior
  1. A.Destructuring — syntax to unpack array elements or object properties into distinct variables
  2. B.Destructuring — the ?. operator that short-circuits to undefined if a reference is null or undefined instead of throwing
  3. C.Destructuring — function parameter values used when the corresponding argument is undefined
  4. D.Destructuring — a ...args parameter that gathers remaining arguments into a real array
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4. What is Template literal?

Junior
  1. A.the ?? operator that returns its right operand only when the left is null or undefined (unlike || which also triggers on any falsy value)
  2. B.syntax to unpack array elements or object properties into distinct variables
  3. C.a backtick string supporting ${} interpolation and multi-line text
  4. D.a ...args parameter that gathers remaining arguments into a real array
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6. Which statement is correct?

Junior
  1. A.Template literal — function parameter values used when the corresponding argument is undefined
  2. B.Template literal — syntax to unpack array elements or object properties into distinct variables
  3. C.Template literal — a backtick string supporting ${} interpolation and multi-line text
  4. D.Template literal — a ...args parameter that gathers remaining arguments into a real array
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7. What is Default parameters?

Junior
  1. A.the ?? operator that returns its right operand only when the left is null or undefined (unlike || which also triggers on any falsy value)
  2. B.a backtick string supporting ${} interpolation and multi-line text
  3. C.function parameter values used when the corresponding argument is undefined
  4. D.a ...args parameter that gathers remaining arguments into a real array
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9. Which statement is correct?

Junior
  1. A.Default parameters — the ?. operator that short-circuits to undefined if a reference is null or undefined instead of throwing
  2. B.Default parameters — a backtick string supporting ${} interpolation and multi-line text
  3. C.Default parameters — function parameter values used when the corresponding argument is undefined
  4. D.Default parameters — a ...args parameter that gathers remaining arguments into a real array
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10. What is Rest parameter?

Junior
  1. A.the ?? operator that returns its right operand only when the left is null or undefined (unlike || which also triggers on any falsy value)
  2. B.syntax to unpack array elements or object properties into distinct variables
  3. C.a ...args parameter that gathers remaining arguments into a real array
  4. D.a backtick string supporting ${} interpolation and multi-line text
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12. Which statement is correct?

Junior
  1. A.Rest parameter — a backtick string supporting ${} interpolation and multi-line text
  2. B.Rest parameter — the ?. operator that short-circuits to undefined if a reference is null or undefined instead of throwing
  3. C.Rest parameter — the ?? operator that returns its right operand only when the left is null or undefined (unlike || which also triggers on any falsy value)
  4. D.Rest parameter — a ...args parameter that gathers remaining arguments into a real array
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13. What is Optional chaining?

Mid
  1. A.a ...args parameter that gathers remaining arguments into a real array
  2. B.the ?. operator that short-circuits to undefined if a reference is null or undefined instead of throwing
  3. C.the ?? operator that returns its right operand only when the left is null or undefined (unlike || which also triggers on any falsy value)
  4. D.syntax to unpack array elements or object properties into distinct variables
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14. Which term means: "the ?. operator that short-circuits to undefined if a reference is null or undefined instead of throwing"?

Mid
  1. A.Optional chaining
  2. B.Default parameters
  3. C.Template literal
  4. D.Nullish coalescing
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15. Which statement is correct?

Mid
  1. A.Optional chaining — function parameter values used when the corresponding argument is undefined
  2. B.Optional chaining — a ...args parameter that gathers remaining arguments into a real array
  3. C.Optional chaining — the ?. operator that short-circuits to undefined if a reference is null or undefined instead of throwing
  4. D.Optional chaining — syntax to unpack array elements or object properties into distinct variables
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16. What is Nullish coalescing?

Mid
  1. A.syntax to unpack array elements or object properties into distinct variables
  2. B.the ?? operator that returns its right operand only when the left is null or undefined (unlike || which also triggers on any falsy value)
  3. C.a backtick string supporting ${} interpolation and multi-line text
  4. D.function parameter values used when the corresponding argument is undefined
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17. Which term means: "the ?? operator that returns its right operand only when the left is null or undefined (unlike || which also triggers on any falsy value)"?

Mid
  1. A.Nullish coalescing
  2. B.Rest parameter
  3. C.Template literal
  4. D.Default parameters
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18. Which statement is correct?

Mid
  1. A.Nullish coalescing — the ?. operator that short-circuits to undefined if a reference is null or undefined instead of throwing
  2. B.Nullish coalescing — the ?? operator that returns its right operand only when the left is null or undefined (unlike || which also triggers on any falsy value)
  3. C.Nullish coalescing — a ...args parameter that gathers remaining arguments into a real array
  4. D.Nullish coalescing — function parameter values used when the corresponding argument is undefined
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