JavaScript functions are blocks of code that can be defined and executed at a later time. They are a fundamental part of JavaScript programming and allow for the creation of reusable code that can be used multiple times in a program.
Functions in JavaScript can be defined using the “function” keyword, followed by the name of the function and a set of parentheses that may contain parameters. The body of the function is enclosed in curly braces {}.
Here’s an example of a basic JavaScript function that takes two parameters and returns their sum:
function sum(a, b) {
return a + b;
}
To call a function, you simply use its name followed by a set of parentheses containing any arguments you want to pass to the function. Here’s an example:
let result = sum(2, 3); // result will be 5
Functions can also be assigned to variables or passed as arguments to other functions. Here’s an example of assigning a function to a variable:
let multiply = function(a, b) {
return a * b;
}
And here’s an example of passing a function as an argument to another function:
function applyOperation(a, b, operation) {
return operation(a, b);
}
let result = applyOperation(2, 3, multiply); // result will be 6
JavaScript also supports arrow functions, which provide a more concise syntax for defining functions. Here’s an example of an arrow function that takes a single parameter and returns its square:
let square = x => x * x;