JavaScript Conditional Statements - Important Points
JavaScript Conditional Statements - MCQ
JavaScript conditional statements are essential components of programming logic that allow developers to control the flow of their code based on certain conditions. In simple terms, conditional statements enable the program to make decisions based on specific criteria.
There are three primary types of conditional statements in JavaScript: if statements, switch statements, and ternary operators. Each of these types of statements has a specific purpose and syntax, which we will discuss in detail below.
If statements
If statements are the most basic type of conditional statements. They are used to execute a block of code if a particular condition is true. Here's an example of an if statement:
if (age >= 18) {
console.log("You are eligible to vote.");
}
In this example, if the variable age is greater than or equal to 18, the code block within the curly braces will be executed.
Switch statements
Switch statements are used when there are multiple possible conditions that need to be evaluated. Switch statements allow developers to define different cases and execute a block of code depending on the value of a variable. Here's an example of a switch statement:
switch (day) {
case 0:
console.log("Today is Sunday");
break;
case 1:
console.log("Today is Monday");
break;
case 2:
console.log("Today is Tuesday");
break;
// and so on
default:
console.log("Invalid day");
break;
}
In this example, the value of the variable day is evaluated, and depending on the value, a different code block is executed.
Ternary operators
Ternary operators are a shorthand way of writing if-else statements. They allow developers to write a single line of code to evaluate a condition and execute one of two code blocks. Here's an example of a ternary operator:
var isAdult = age >= 18 ? "Yes" : "No";
In this example, if the variable age is greater than or equal to 18, the value of isAdult will be "Yes". Otherwise, it will be "No".
It's important to note that all conditional statements require a condition to be evaluated. This condition must return a boolean value, which is either true or false. In addition, it's crucial to use proper syntax and appropriate code blocks to avoid errors and bugs.
List of all conditional statements in JavaScript
If statements: If statements are used to execute a block of code if a particular condition is true.
If-else statements: If-else statements are used to execute one block of code if a condition is true, and another block of code if the condition is false.
Else-if statements: Else-if statements are used to evaluate multiple conditions and execute different blocks of code based on the conditions.
Switch statements: Switch statements allow developers to define different cases and execute a block of code depending on the value of a variable.
Ternary operators: Ternary operators are a shorthand way of writing if-else statements.
Short-circuit evaluation: Short-circuit evaluation is a technique used to determine the value of a logical expression by evaluating the minimum number of operands necessary to determine the final outcome.
Each of these conditional statements has its own syntax and purpose, and understanding them is essential for writing efficient and effective JavaScript code.