This detailed tutorial shows how to implement pure functions in JavaScript that are deterministic and referentially transparent, and create no side effects.

Master JavaScript programming with this complete beginner’s tutorial. Learn the fundamentals of JavaScript, a versatile programming language.

Learn the basics about functions in JavaScript: Basic theory about functions in JavaScript. Learn the syntax on how to create functions. How to call functions. What are function parameters and the ...

‘Higher-order functions’ is a fancy term for functions that take other functions as arguments or that return functions. Very powerful!

For starters, let’s create a function that draws a watercolor spot with a given position, radius, and hue. P5.js gives us a function to draw an ellipse that we already used last week.