Matrix Code micro:bit

matrix.js

let frame = 0
let drops: { col: number, row: number }[] = []
let addDrops = 3
let pauseDuration = 100

// Press A: Make animation slower
input.onButtonPressed(Button.A, function () {
    pauseDuration *= 1.1
})

// Press B: Make animation faster
input.onButtonPressed(Button.B, function () {
    pauseDuration *= 0.9
})

basic.forever(function () {
    frame += 1
    // Add a new drop
    for (let index = 0; index < addDrops; index++) {
        drops.push({
            col: randint(0, 4),
            row: 0
        })
    }
    // Clear screen
    basic.clearScreen()
    // Render drops
    for (let i = 0; i <= drops.length - 1; i++) {
        led.plot(drops[i].col, drops[i].row)
    }
    // Move drops down
    for (let j = 0; j <= drops.length - 1; j++) {
        ++drops[j].row
    }
    // Remove drops that are outside of the screen
    drops = drops.filter(({row}) => row <= 4)
    // Wait a little
    basic.pause(pauseDuration)
})