JavaScript Basics u0026 Fundamentals Challenge Quiz

Test your knowledge of JavaScript essentials including syntax, variables, data types, operators, and type conversion. This quiz is designed to assess your understanding of core JavaScript concepts and their correct applications.

1. Variable Declaration Nuance

   Which statement correctly declares a block-scoped variable that cannot be reassigned in JavaScript?

   1. const fruit = 'apple';
   2. block fruit = 'apple';
   3. var fruit = 'apple';
   4. let fruit = 'apple';
   5. static fruit = 'apple';

2. Comment Syntax Challenge

   Which of the following is the correct way to write a multi-line comment in JavaScript?

   1. ' This is a comment
   2. # This is a comment #
   3. // This is a comment //
   4. u003C!-- This is a comment --u003E
   5. /* This is a comment */

3. Type Conversion Intricacies

   Given let str = '123'; which code snippet properly converts str to a number?

   1. String(str);
   2. Number(str);
   3. str.toFloat();
   4. cast(str, Number);
   5. parseChar(str);

4. Hoisting and Scope

   What will be logged by the following code: console.log(x); var x = 5;

   1. TypeError
   2. null
   3. undefined
   4. ReferenceError
   5. '5'

5. Strict Equality Operator

   Which operator checks both value and type equality in JavaScript?

   1. ==
   2. !=
   3. =
   4. !===
   5. ===

6. Bitwise Operator Usage

   What is the result of the expression: 5 u0026 3?

   1. 7
   2. 8
   3. 1
   4. 2
   5. 0

7. Logical Operator Precedence

   What does the expression true || false u0026u0026 false evaluate to?

   1. undefined
   2. false
   3. NaN
   4. null
   5. true

8. Immutable Binding

   Which statement about variables declared with const is correct?

   1. The value assigned to a const variable can be reassigned later.
   2. const variable must be initialized at the time of declaration.
   3. const makes deep objects primitive.
   4. const always creates a global variable.
   5. A const declaration can be left uninitialized.

9. Typeof Operator Deep Dive

   What is the result of typeof null in JavaScript?

   1. 'null'
   2. 'object'
   3. 'Void'
   4. 'NaN'
   5. 'undefined'

10. String to Boolean Conversion

    Given let str = 'false'; what does Boolean(str) evaluate to?

    1. true
    2. NaN
    3. undefined
    4. false
    5. null

11. Variable Scope Complexity

    Which keyword ensures a variable only exists within its containing block or statement?

    1. static
    2. let
    3. define
    4. var
    5. global

12. Floating Point Peculiarities

    What will be logged by console.log(0.1 + 0.2 === 0.3)?

    1. TypeError
    2. undefined
    3. true
    4. false
    5. NaN

13. Unary Plus Operator

    Which expression converts the string '8' to the number 8?

    1. -'8'
    2. parseChar('8')
    3. 8/'8'
    4. '8'+0
    5. +'8'

14. Logical NOT Operator

    What is the result of !!undefined in JavaScript?

    1. false
    2. true
    3. NaN
    4. undefined
    5. null

15. Operator Associativity Detail

    What does 3 + 4 * 2 evaluate to in JavaScript?

    1. 11
    2. 8
    3. 16
    4. 14
    5. 10