Conditional structures in JavaScript

Conditional structures in JavaScript are used to make decisions in your code based on certain conditions. They allow you to execute different code blocks depending on whether a condition evaluates to true or false. Conditional structures are essential for creating responsive and dynamic applications. JavaScript provides several conditional statements and structures:

if Statement:

The if statement is the most basic conditional structure. It allows you to execute a block of code if a specified condition is true. If the condition is false, the code block is skipped.

if (condition) {
  // Code to execute if the condition is true

else Statement:

The else statement is often used in conjunction with the if statement. It allows you to specify an alternative block of code to execute if the condition in the if statement is false.

if (condition) {
  // Code to execute if the condition is true
} else {
  // Code to execute if the condition is false

else if Statement:

The else if statement can be used to check multiple conditions in sequence. It allows you to specify additional conditions to test if the previous conditions are false.

if (condition1) {
  // Code to execute if condition1 is true
} else if (condition2) {
  // Code to execute if condition2 is true
} else {
  // Code to execute if none of the conditions are true

Ternary (Conditional) Operator (? :):

The ternary operator is a concise way to express conditional logic. It evaluates a condition and returns one of two expressions based on whether the condition is true or false.

let result = condition ? expressionIfTrue : expressionIfFalse;

switch Statement:

The switch statement is used to select one of many code blocks to be executed. It compares an expression against multiple case values and executes the code block associated with the matching case.

switch (expression) {
  case value1:
    // Code to execute if expression matches value1
  case value2:
    // Code to execute if expression matches value2
  // ...
    // Code to execute if no cases match the expression

Conditional (Ternary) Operator (&& and ||):

The logical AND (&&) and logical OR (||) operators can be used for conditional execution. They evaluate expressions and return the result of the last evaluated expression.

  • expr1 && expr2: Returns expr1 if it’s falsy, otherwise returns expr2.
  • expr1 || expr2: Returns expr1 if it’s truthy, otherwise returns expr2.

Conditional structures are used in various scenarios, such as validating user input, handling different cases in your code, and creating interactive web applications. Understanding how to use these structures effectively is crucial for writing logic in JavaScript.

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