Different ways of writing functions in JavaScript

in My first phase with Flatiron school i learned how to write functions in a deferent way.

What is a Function?

• A function in JavaScript is similar to a procedure—a set of statements that performs a task or calculates a value, but for a procedure to qualify as a function, it should take some input and return an output where there is some obvious relationship between the input and the output.

Types of writing a function:

• Function Declaration
• Function Expression
• Arrow Function

What is a Function Declaration:

• The function declaration (function statement) defines a function with the specified parameters. You can also define functions using the Function constructor and a function expression

• An example of a function declaration:

functions are declared with the following syntax.

function functionName(parameters) {
  // code to be executed
}

Declared functions are not executed immediately. They are "saved for later use", and will be executed later, when they are invoked (called upon).

function myFunction(a, b) {
  return a * b;
}

What is a Function Expression:

• Function Expression is another way to define a function in JavaScript. Here we define a function using a variable and store the returned value in that variable.

• An example of a function expression:

A function expression can be stored in a variable:

const x = function (a , b) {return a * b};

After a function expression has been stored in a variable, the variable can be used as a function:

const x = function (a, b) {return a * b};
let z = x(4, 3);

What is an Arrow Function:

• Arrow functions are a new way to write anonymous function expressions, and are similar to lambda functions in some other programming languages, such as Python.

• An example of a function arrow:

Before Arrow function

Piece = function() {
  return "One Piece!";
}

After Arrow function

Piece = () => {
  return "One Piece!";
}

It gets shorter! If the function has only one statement, and the statement returns a value, you can remove the brackets and the return keyword:

Piece = () => "One Piece!";