Using classes to group similar functions together

Sunday, Aug 9, 2020

Besides creating modular objects, classes can also be used to group similar functions together. Let's say in a game, we want to calculate new position of a player as it moves forward or backward. We can wrap the two functions in a class and then call it whenever we need:

class Position{
    // return new position by subtracting delta from old
    newPositionReverse(x, delta = 1){
        return x - delta;

    // return new position by adding delta to old
    newPositionForward(x, delta = 1){
        return x + delta;

const pos = new Position();

// 9
console.log(pos.newPositionReverse(10, 5));
// 5
// 11
console.log(pos.newPositionForward(10, 5));
// 15

Typically, we will not use the functions in the same file where we created these. Instead, our main program may need functions from multiple files (called modules in this context). I have updated my older note to show how it is accomplished.