Control flow in JavaScript is a fundamental concept that dictates the order in which statements are executed within a script. It enables developers to control the flow of program execution based on conditions and loops. Understanding control flow is essential for writing efficient and logic-driven JavaScript code.
Conditional Statements
Conditional statements allow developers to execute code based on specific conditions. JavaScript provides several types of conditional statements:
if statement: This statement evaluates a condition and executes a block of code if the condition is true. For example:
if (condition) {
// Code block to execute if condition is true
}
if...else statement: It executes one block of code if a condition is true and another block if the condition is false. Example:
if (condition) {
// Code block to execute if condition is true
} else {
// Code block to execute if condition is false
}
else if statement: This statement allows for multiple conditions to be checked sequentially. Example:
if (condition1) {
// Code block to execute if condition1 is true
} else if (condition2) {
// Code block to execute if condition2 is true
} else {
// Code block to execute if neither condition1 nor condition2 is true
}
switch statement: It evaluates an expression and executes code based on a matching case label. Example:
switch (expression) {
case value1:
// Code block to execute if expression equals value1
break;
case value2:
// Code block to execute if expression equals value2
break;
default:
// Code block to execute if expression doesn't match any case
}
Loops
Loops are used to execute a block of code repeatedly until a specified condition is met. JavaScript supports different types of loops:
for loop: Executes a block of code a specified number of times. Example:
for (initialization; condition; iteration) {
// Code block to execute