Practice JavaScript Basics MCQ questions with detailed explanations and clear answer validation. These MCQs help you revise core concepts, compare close options, and improve accuracy for interviews, certification exams, and technical screening rounds. Use this updated 2026 set to strengthen fundamentals and confidence.
Q51. Which statement about call/apply/bind is most accurate?
Select an answer to check.
Answer: Set this and args explicitly.
Here, Set this and args explicitly. is the right choice. Bind returns new function. It aligns directly with what the question asks about which statement about call/apply/bind is most accurate. Competing choices sound plausible, but they miss the key condition.
Q52. How is call/apply/bind best characterized?
Select an answer to check.
Answer: Set this and args explicitly.
In this case, Set this and args explicitly. is correct. Bind returns new function. It aligns directly with what the question asks about how is call/apply/bind best characterized. Competing choices sound plausible, but they miss the key condition.
Q53. Which option best describes closures?
Select an answer to check.
Answer: Function plus its captured lexical scope.
The best option here is Function plus its captured lexical scope.. Common for encapsulation. It aligns directly with what the question asks about which option best describes closures. Competing choices sound plausible, but they miss the key condition.
Q54. What is the primary purpose of closures?
Select an answer to check.
Answer: Function plus its captured lexical scope.
For this question, Function plus its captured lexical scope. is correct. Common for encapsulation. It aligns directly with what the question asks about what is the primary purpose of closures. Competing choices sound plausible, but they miss the key condition.
Q55. Which statement about closures is most accurate?
Select an answer to check.
Answer: Function plus its captured lexical scope.
Function plus its captured lexical scope. is the correct answer here. Common for encapsulation. It aligns directly with what the question asks about which statement about closures is most accurate. Competing choices sound plausible, but they miss the key condition.
Q56. How is closures best characterized?
Select an answer to check.
Answer: Function plus its captured lexical scope.
Here, Function plus its captured lexical scope. is the right choice. Common for encapsulation. This matches the core idea being tested around how is closures best characterized. Competing choices sound plausible, but they miss the key condition.
Q57. Which option best describes the prototype chain?
Select an answer to check.
Answer: Objects link to prototype for property lookup.
In this case, Objects link to prototype for property lookup. is correct. Foundation of inheritance in JS. This matches the core idea being tested around which option best describes the prototype chain. Competing choices sound plausible, but they miss the key condition.
Q58. What is the primary purpose of the prototype chain?
Select an answer to check.
Answer: Objects link to prototype for property lookup.
The best option here is Objects link to prototype for property lookup.. Foundation of inheritance in JS. This matches the core idea being tested around what is the primary purpose of the prototype. Competing choices sound plausible, but they miss the key condition.
Q59. Which statement about the prototype chain is most accurate?
Select an answer to check.
Answer: Objects link to prototype for property lookup.
For this question, Objects link to prototype for property lookup. is correct. Foundation of inheritance in JS. This matches the core idea being tested around which statement about the prototype chain is most. Competing choices sound plausible, but they miss the key condition.
Q60. How is the prototype chain best characterized?
Select an answer to check.
Answer: Objects link to prototype for property lookup.
Objects link to prototype for property lookup. is the correct answer here. Foundation of inheritance in JS. This matches the core idea being tested around how is the prototype chain best characterized. Competing choices sound plausible, but they miss the key condition.
Q61. Which option best describes classes?
Select an answer to check.
Answer: Syntactic sugar over prototype-based inheritance.
Here, Syntactic sugar over prototype-based inheritance. is the right choice. ES2015 feature. That is exactly the concept behind which option best describes classes in this context. Competing choices sound plausible, but they miss the key condition.
Q62. What is the primary purpose of classes?
Select an answer to check.
Answer: Syntactic sugar over prototype-based inheritance.
In this case, Syntactic sugar over prototype-based inheritance. is correct. ES2015 feature. That is exactly the concept behind what is the primary purpose of classes in this context. Competing choices sound plausible, but they miss the key condition.
Q63. Which statement about classes is most accurate?
Select an answer to check.
Answer: Syntactic sugar over prototype-based inheritance.
The best option here is Syntactic sugar over prototype-based inheritance.. ES2015 feature. That is exactly the concept behind which statement about classes is most accurate in this context. Competing choices sound plausible, but they miss the key condition.
Q64. How is classes best characterized?
Select an answer to check.
Answer: Syntactic sugar over prototype-based inheritance.
For this question, Syntactic sugar over prototype-based inheritance. is correct. ES2015 feature. That is exactly the concept behind how is classes best characterized in this context. Competing choices sound plausible, but they miss the key condition.
Q65. Which option best describes template literals?
Select an answer to check.
Answer: Backtick strings with ${} interpolation.
Backtick strings with ${} interpolation. is the correct answer here. Multi-line and embedded expressions. That is exactly the concept behind which option best describes template literals in this context. Competing choices sound plausible, but they miss the key condition.
Q66. What is the primary purpose of template literals?
Select an answer to check.
Answer: Backtick strings with ${} interpolation.
Here, Backtick strings with ${} interpolation. is the right choice. Multi-line and embedded expressions. It fits the requirement in the prompt about what is the primary purpose of template literals. Competing choices sound plausible, but they miss the key condition.
Q67. Which statement about template literals is most accurate?
Select an answer to check.
Answer: Backtick strings with ${} interpolation.
In this case, Backtick strings with ${} interpolation. is correct. Multi-line and embedded expressions. It fits the requirement in the prompt about which statement about template literals is most accurate. Competing choices sound plausible, but they miss the key condition.
Q68. How is template literals best characterized?
Select an answer to check.
Answer: Backtick strings with ${} interpolation.
The best option here is Backtick strings with ${} interpolation.. Multi-line and embedded expressions. It fits the requirement in the prompt about how is template literals best characterized. Competing choices sound plausible, but they miss the key condition.
Q69. Which option best describes destructuring?
Select an answer to check.
Answer: Unpack from arrays/objects into variables.
For this question, Unpack from arrays/objects into variables. is correct. Const { a, b } = obj. It fits the requirement in the prompt about which option best describes destructuring. Competing choices sound plausible, but they miss the key condition.
Q70. What is the primary purpose of destructuring?
Select an answer to check.
Answer: Unpack from arrays/objects into variables.
Unpack from arrays/objects into variables. is the correct answer here. Const { a, b } = obj. It fits the requirement in the prompt about what is the primary purpose of destructuring. Competing choices sound plausible, but they miss the key condition.
Q71. Which statement about destructuring is most accurate?
Select an answer to check.
Answer: Unpack from arrays/objects into variables.
Here, Unpack from arrays/objects into variables. is the right choice. Const { a, b } = obj. This is the most accurate statement for which statement about destructuring is most accurate. Competing choices sound plausible, but they miss the key condition.
Q72. How is destructuring best characterized?
Select an answer to check.
Answer: Unpack from arrays/objects into variables.
In this case, Unpack from arrays/objects into variables. is correct. Const { a, b } = obj. This is the most accurate statement for how is destructuring best characterized. Competing choices sound plausible, but they miss the key condition.
Q73. Which option best describes spread/rest?
Select an answer to check.
Answer: ... gathers/expands arrays/objects.
The best option here is ... gathers/expands arrays/objects.. Useful for copies, args. This is the most accurate statement for which option best describes spread/rest. Competing choices sound plausible, but they miss the key condition.
Q74. What is the primary purpose of spread/rest?
Select an answer to check.
Answer: ... gathers/expands arrays/objects.
For this question, ... gathers/expands arrays/objects. is correct. Useful for copies, args. This is the most accurate statement for what is the primary purpose of spread/rest. Competing choices sound plausible, but they miss the key condition.
Q75. Which statement about spread/rest is most accurate?
Select an answer to check.
Answer: ... gathers/expands arrays/objects.
... gathers/expands arrays/objects. is the correct answer here. Useful for copies, args. This is the most accurate statement for which statement about spread/rest is most accurate. Competing choices sound plausible, but they miss the key condition.
Q76. How is spread/rest best characterized?
Select an answer to check.
Answer: ... gathers/expands arrays/objects.
Here, ... gathers/expands arrays/objects. is the right choice. Useful for copies, args. It aligns directly with what the question asks about how is spread/rest best characterized. The remaining choices fail because they don’t satisfy the full definition.
Q77. Which option best describes modules (ESM)?
Select an answer to check.
Answer: import/export of modules.
In this case, import/export of modules. is correct. Native module system. It aligns directly with what the question asks about which option best describes modules (esm). The remaining choices fail because they don’t satisfy the full definition.
Q78. What is the primary purpose of modules (ESM)?
Select an answer to check.
Answer: import/export of modules.
The best option here is import/export of modules.. Native module system. It aligns directly with what the question asks about what is the primary purpose of modules (esm). The remaining choices fail because they don’t satisfy the full definition.
Q79. Which statement about modules (ESM) is most accurate?
Select an answer to check.
Answer: import/export of modules.
For this question, import/export of modules. is correct. Native module system. It aligns directly with what the question asks about which statement about modules (esm) is most accurate. The remaining choices fail because they don’t satisfy the full definition.
Q80. How is modules (ESM) best characterized?
Select an answer to check.
Answer: import/export of modules.
import/export of modules. is the correct answer here. Native module system. It aligns directly with what the question asks about how is modules (esm) best characterized. The remaining choices fail because they don’t satisfy the full definition.
Q81. Which option best describes CommonJS?
Select an answer to check.
Answer: require/module.exports module system.
Here, require/module.exports module system. is the right choice. Used in Node legacy. This matches the core idea being tested around which option best describes commonjs. The remaining choices fail because they don’t satisfy the full definition.
Q82. What is the primary purpose of CommonJS?
Select an answer to check.
Answer: require/module.exports module system.
In this case, require/module.exports module system. is correct. Used in Node legacy. This matches the core idea being tested around what is the primary purpose of commonjs. The remaining choices fail because they don’t satisfy the full definition.
Q83. Which statement about CommonJS is most accurate?
Select an answer to check.
Answer: require/module.exports module system.
The best option here is require/module.exports module system.. Used in Node legacy. This matches the core idea being tested around which statement about commonjs is most accurate. The remaining choices fail because they don’t satisfy the full definition.
Q84. How is CommonJS best characterized?
Select an answer to check.
Answer: require/module.exports module system.
For this question, require/module.exports module system. is correct. Used in Node legacy. This matches the core idea being tested around how is commonjs best characterized. The remaining choices fail because they don’t satisfy the full definition.
Q85. Which option best describes strict mode?
Select an answer to check.
Answer: Stricter parsing/error semantics.
Stricter parsing/error semantics. is the correct answer here. 'use strict' or modules default. This matches the core idea being tested around which option best describes strict mode. The remaining choices fail because they don’t satisfy the full definition.
Q86. What is the primary purpose of strict mode?
Select an answer to check.
Answer: Stricter parsing/error semantics.
Here, Stricter parsing/error semantics. is the right choice. 'use strict' or modules default. That is exactly the concept behind what is the primary purpose of strict mode in this context. The remaining choices fail because they don’t satisfy the full definition.
Q87. Which statement about strict mode is most accurate?
Select an answer to check.
Answer: Stricter parsing/error semantics.
In this case, Stricter parsing/error semantics. is correct. 'use strict' or modules default. That is exactly the concept behind which statement about strict mode is most accurate in this context. The remaining choices fail because they don’t satisfy the full definition.
Q88. How is strict mode best characterized?
Select an answer to check.
Answer: Stricter parsing/error semantics.
The best option here is Stricter parsing/error semantics.. 'use strict' or modules default. That is exactly the concept behind how is strict mode best characterized in this context. The remaining choices fail because they don’t satisfy the full definition.
Q89. Which option best describes Promises?
Select an answer to check.
Answer: Object representing eventual completion.
For this question, Object representing eventual completion. is correct. Then/catch/finally. That is exactly the concept behind which option best describes promises in this context. The remaining choices fail because they don’t satisfy the full definition.
Q90. What is the primary purpose of Promises?
Select an answer to check.
Answer: Object representing eventual completion.
Object representing eventual completion. is the correct answer here. Then/catch/finally. That is exactly the concept behind what is the primary purpose of promises in this context. The remaining choices fail because they don’t satisfy the full definition.
Q91. Which statement about Promises is most accurate?
Select an answer to check.
Answer: Object representing eventual completion.
Here, Object representing eventual completion. is the right choice. Then/catch/finally. It fits the requirement in the prompt about which statement about promises is most accurate. The remaining choices fail because they don’t satisfy the full definition.
Q92. How is Promises best characterized?
Select an answer to check.
Answer: Object representing eventual completion.
In this case, Object representing eventual completion. is correct. Then/catch/finally. It fits the requirement in the prompt about how is promises best characterized. The remaining choices fail because they don’t satisfy the full definition.
Q93. Which option best describes async/await?
Select an answer to check.
Answer: Sugar for promises.
The best option here is Sugar for promises.. Read like synchronous code. It fits the requirement in the prompt about which option best describes async/await. The remaining choices fail because they don’t satisfy the full definition.
Q94. What is the primary purpose of async/await?
Select an answer to check.
Answer: Sugar for promises.
For this question, Sugar for promises. is correct. Read like synchronous code. It fits the requirement in the prompt about what is the primary purpose of async/await. The remaining choices fail because they don’t satisfy the full definition.
Q95. Which statement about async/await is most accurate?
Select an answer to check.
Answer: Sugar for promises.
Sugar for promises. is the correct answer here. Read like synchronous code. It fits the requirement in the prompt about which statement about async/await is most accurate. The remaining choices fail because they don’t satisfy the full definition.
Q96. How is async/await best characterized?
Select an answer to check.
Answer: Sugar for promises.
Here, Sugar for promises. is the right choice. Read like synchronous code. This is the most accurate statement for how is async/await best characterized. The remaining choices fail because they don’t satisfy the full definition.
Q97. Which option best describes the event loop?
Select an answer to check.
Answer: Schedules tasks/microtasks for execution.
In this case, Schedules tasks/microtasks for execution. is correct. Microtasks run before macrotasks. This is the most accurate statement for which option best describes the event loop. The remaining choices fail because they don’t satisfy the full definition.
Q98. What is the primary purpose of the event loop?
Select an answer to check.
Answer: Schedules tasks/microtasks for execution.
The best option here is Schedules tasks/microtasks for execution.. Microtasks run before macrotasks. This is the most accurate statement for what is the primary purpose of the event. The remaining choices fail because they don’t satisfy the full definition.
Q99. Which statement about the event loop is most accurate?
Select an answer to check.
Answer: Schedules tasks/microtasks for execution.
For this question, Schedules tasks/microtasks for execution. is correct. Microtasks run before macrotasks. This is the most accurate statement for which statement about the event loop is most. The remaining choices fail because they don’t satisfy the full definition.
Q100. How is the event loop best characterized?
Select an answer to check.
Answer: Schedules tasks/microtasks for execution.
Schedules tasks/microtasks for execution. is the correct answer here. Microtasks run before macrotasks. This is the most accurate statement for how is the event loop best characterized. The remaining choices fail because they don’t satisfy the full definition.