Random Colour Generator JS

// `getRandomHex` is a curried function, that takes `from`,
// then it takes `to` and returns a function that when called
// gives you a random hex number between `from` and `to`
const getRandomHex = from => to => () =>
    // `.toString(16)` converts the number to a hex string
    // so if you had (13).toString(16) it would return "d"
    Math.floor(Math.random() * (to - from) + from).toString(16);

// `getRangedRandomColor` is also a curried function that takes the same `from`
// and then `to`, but this one returns a string of the form "#RRGGBB"
const getRangedRandomColor = from => to => () =>
    // We used template literals for it with the back-ticks: ``
    // We start with a `#`
    `#${
        // Then we create a new array of 6 elements, we need to spread it
        // because being 6 `empty` elements, we can't map over it and
        // when we spread it with `...` it becomes an array of 6 `undefined`
        [...Array(6)]
            // We then map over that array calling `getRandomHex` on every item
            // so we effectively get 6 random hex values
            .map(getRandomHex(from)(to))
            // Join those elements into a single string and tada!
            .join("")
    }`;

// Now because `getRangedRandomColor` is a curried function, calling it here
// with only 2 arguments gives us a function like this: () => "#RRGGBB"
// So `getRandomColor` is a function that gives a color with values from 0 to f
const getRandomColor = getRangedRandomColor(0x0)(0xf);

// `getRandomColorLight` is the same, but from 7 to f
const getRandomColorLight = getRangedRandomColor(0x7)(0xf);

// and `getRandomColorDark` is the same, but from 0 to 7
const getRandomColorDark = getRangedRandomColor(0x0)(0x7);