JavaScript Functions

Functions Study Path

Learn Functions in the Right Order:

• First the idea
• Then how to make them
• Then how to use them

Step 1Beginner

What are Functions?

• Functions are reusable code blocks designed for particular tasks
• Functions are executed when they are called or invoked
• Functions are fundamental in all programming languages

Step 2Beginner

Calling Functions

• Functions are executed when they are called or invoked
• You call a function by adding parentheses to its name: name()

Step 3Beginner

Function Parameters

• Parameters allow you to send values to a function
• Parameters are listed in parentheses in the function definition

Step 4Beginner

Function Return Values

• A function can return a value back to the code that called it
• The return statement is used to return a value from a function

Step 5Intermediate

Function Arguments

• Function parameters and arguments are distinct concepts
• Parameters are the names listed in the function definition
• Arguments are the values received by the function

Step 6Intermediate

Function Expressions

• A function expression is a function stored in a variable
• The variable name can be used to call the function

Step 7Intermediate

Arrow Functions

• Arrow Functions is a short syntax for function expressions
• You can skip the function keyword
• You can skip the return keyword
• You can skip the curly brackets

Step 8Intermediate

Function Quiz

• Test your knowledge of JavaScript functions
• The quiz uses the examples you learned in the tutorial

Advanced Functions Study Path

Step 1Advanced

JavaScript Definitions

• Function declarations
• Function Expression
• Arrow Functions
• Function Constructors

Step 2Advanced

JavaScript Callbacks

A JavaScript callback is a function passed as an argument to another function, which is then executed (or "called back") at a later point in time to complete a specific task.

Step 3Advanced

The this Keyword

How this works (especially inside objects).

How this is decided by how it is called.

Step 4Advanced

The call() Method

Call a function with a chosen this.

Pass a list of arguments.

Step 5Advanced

The apply() Method

Call a function with a chosen this.

Pass an array of arguments.

Step 6Advanced

The bind() Method

Call a function with a chosen this.

Use bind() when you need a function to run later with the same this.

Step 7Advanced

Self Invoked - IIFE

Self-starting functions.

Step 8Advanced

JavaScript Closures

Functions that remember their scope

Learn how functions can remember variables after the outer function finishes.

Step 9Advanced

Function References

Function Object Methods & Properties.