Crazy Streams

input.js

var through = require("through")
    , KEYS = {
        "37": "left"
        , "38": "up"
        , "39": "right"
        , "40": "down"
    }
    
module.exports = Input

function Input() {
    var stream = through()

    window.addEventListener("keydown", listenOnKeys)

    return stream

    function listenOnKeys(event) {
        var key = KEYS[event.which]
        
        if (key) {
            stream.write(key)
        }
    }
}

positionChange.js

module.exports = PositionChangeStream

function PositionChangeStream(speed) {
    var id = uuid()
    return through(translateInput)

    function translateInput(type) {
        var changes = {}
        if (type === "left") {
            changes.x = -speed
        } else if (type === "right") {
            changes.x = +speed
        } else if (type === "up") {
            changes.y = -speed
        } else if (type === "down") {
            changes.y = +speed
        }

        this.emit("data", [changes, Date.now(), id])
    }
}