JavaScript Functions
Duration : 00:01:30
Functions:
Functions in JavaScript are blocks of code that can be defined once and reused multiple times throughout your program. They encapsulate a set of instructions and can accept input values, process them, and optionally return a result.Example:
function greet(name) {
return 'Hello, ${name}!';
}
console.log(greet("John")); // Output: Hello, John! Anonymous Functions:
Anonymous functions are functions without a designated name. They are often used as arguments for other functions, or in scenarios where a short-lived function is required.Example:
let sum = function(x, y) {
return x + y;
};
console.log(sum(3, 5)); // Output: 8
Function Expressions:
Function expressions are a way to define functions as values within variables. This allows you to treat functions like any other data type and pass them around in your code.Example:
let multiply = function(a, b) {
return a * b;
};
console.log(multiply(2, 4)); // Output: 8
Function Parameters:
Function parameters are the placeholders for values that a function can accept when it's called. These values are then used within the function's code.Example:
function exponent(base, power) {
return Math.pow(base, power);
}
console.log(exponent(3, 2)); // Output: 9
Function Declaration:
Function declarations define named functions with a given name that can be called later in the code. They are hoisted to the top of their scope.Example:
function sayHello(name) {
console.log('Hello, ${name}!');
}
sayHello("Mohan"); // Output: Hello, Mohan!
Calling Functions:
Calling a function means executing the code within the function's body. This is done by using the function's name followed by parentheses.Example:
function double(num) {
return num * 2;
}
let result = double(7);
console.log(result); // Output: 14
Arrow Functions (ES6):
Arrow functions are a concise way to write functions introduced in ES6. They have a simpler syntax and automatically capture the 'this' value of the surrounding context.Example:
let divide = (x, y) => x / y;
console.log(divide(10, 2)); // Output: 5
Return Keyword:
The 'return' keyword is used within a function to specify the value that the function should produce as its output. Once a 'return' statement is encountered, the function exits.Example:
function square(num) {
return num * num;
}
console.log(square(4)); // Output: 16
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