/
keyboard-arrows.js
62 lines (44 loc) · 1.19 KB
/
keyboard-arrows.js
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var document = require("global/document")
var signal = require("../signal/signal")
var KEYS = {
"37": "left"
, "38": "up"
, "39": "right"
, "40": "down"
}
module.exports = KeyboardArrows
// Signal { x: Number, y: Number }
function KeyboardArrows() {
var validKeys = [37, 38, 39, 40]
return signal(function (next) {
var down = {}
document.addEventListener("keyup", function onup(ev) {
if (ev.which in KEYS) {
var key = KEYS[ev.which]
down[key] = false
next(getState())
}
})
document.addEventListener("keydown", function ondown(ev) {
if (ev.which in KEYS) {
var key = KEYS[ev.which]
down[key] = true
next(getState())
}
})
function getState() {
var x = 0, y = 0
if (down.up) {
y = 1
} else if (down.down) {
y = -1
}
if (down.left) {
x = -1
} else if (down.right) {
x = 1
}
return { x: x, y: y }
}
}, { x: 0, y: 0 })
}