Quiz: Introduction to JS - 2 - Software Development MCQ

JavaScript is a high-level, interpreted programming language primarily used for web development.

JavaScript does not have a dedicated "Character" data type. Characters are represented as strings of length 1.

Functions in JavaScript allow for code organization and reusability by encapsulating a set of instructions.

Single-line comments in JavaScript are denoted by //.

Angular is a popular JavaScript framework for building web applications.

The + operator, when one operand is a string, performs string concatenation. Therefore, "2" is treated as a string, and the result is "22".

The - operator performs arithmetic subtraction. In this case, the string "2" is converted to the number 2, and the result is 2 - 1 = 1.

Variable hoisting causes the declaration of 'var x' inside the function to be hoisted to the top. However, it is initialized with the value 'undefined' before the assignment. Therefore, the output is 'undefined'.

The 'setTimeout' function is asynchronous. By the time the 'console.log(i)' is executed, the loop has already completed, and the value of 'i' is 3. Therefore, the output is 0, 1, 2.

The 'typeof' operator returns "number" for NaN (Not-a-Number) because NaN is a special numeric value in JavaScript.

The variable 'x' is declared using 'let' inside the immediately-invoked function expression (IIFE). Since 'let' has block scope, the declaration of 'x' inside the function creates a new variable that is not accessible before the declaration.

The variable 'x' is declared using 'let' inside the function 'foo'. The 'console.log(x)' line tries to access 'x' before it is declared, resulting in a ReferenceError.

The 'var' declaration inside the if block is hoisted to the top of the function scope. However, since the condition is always false, the assignment 'var x = 20' is never executed. The output is 10.

The 'console.log(x)' line tries to access 'x' before it is declared inside the block. Since 'let' has block scope, the declaration of 'x' shadows the outer 'x' variable, and it is not accessible before its declaration.

The 'console.log(x)' line tries to access 'x' before it is declared inside the inner block. Since 'let' has block scope, the declaration of 'x' inside the inner block shadows the outer 'x' variable, and it is not accessible before its declaration.