Bare bones event broker

broker.js

const channels = {}

export const radio = {
    listen (event, callback) {
        if (!channels[event]) {
            channels[event] = []
        }
        channels[event].push(callback)
    },
    broadcast (event, data = {}) {
        const listeners = channels[event] || []
        for (const callback of listeners) {
            callback(data)
        }
    }
}

Kiln.js

// Import the radio
import { radio } from "./broker.js"

// Listen on a channel
radio.listen("potteryCreated", data => {
    // Use the data that was broadcast on the `potteryCreated` channel
    const firedPottery = firePottery(data.piece, 2100)
    
    // Broadcast on another channel with new data
    radio.broadcast("potteryFired", { firedPottery })
})

export const firePottery = (piece, temperature) => {
    piece.fired = true
    if (temperature >= 2200) {
        piece.cracked = true
    } else {
        piece.cracked = false
    }

    return piece
}