diff --git a/.npmignore b/.npmignore
index ac96530..4668b27 100644
--- a/.npmignore
+++ b/.npmignore
@@ -1,3 +1,4 @@
+examples
devtools-extension
test
.github
diff --git a/examples/events/app.js b/examples/events/app.js
new file mode 100644
index 0000000..228032b
--- /dev/null
+++ b/examples/events/app.js
@@ -0,0 +1,119 @@
+import ECS from 'ecs'
+
+
+const WIDGET_QUERY = [ 'widget' ]
+
+const constants = {
+ FIXED_STEP_MS: 16, // fixed steps run @ 62.5fps (16ms per frame)
+}
+
+const Global = {
+ world: undefined, // ECS instance
+
+ // timekeeping (in milliseconds)
+ lastFrameTime: 0, // time the last frame ran
+ accumulator: 0, // accumulate time to run ticks at a fixed rate
+
+ tick: 0, // total number of frames elapsed
+}
+
+
+async function main () {
+ // init
+ Global.world = ECS.createWorld()
+
+ // add all of the game's systems
+ ECS.addSystem(Global.world, widgetSpawnerSystem)
+ ECS.addSystem(Global.world, scoreSystem)
+
+ // start the simulation loop
+ simLoop()
+}
+
+
+function simLoop () {
+ const world = Global.world
+ const { FIXED_STEP_MS } = constants
+
+ const newTime = performance.now()
+ const frameTime = newTime - Global.lastFrameTime
+ Global.lastFrameTime = newTime
+
+ Global.accumulator += frameTime
+
+ // reset accumulator when > 2 seconds of time has elapsed since last step
+ // e.g., when the game window is restored after being hidden for a while
+ if (Global.accumulator > 2000)
+ Global.accumulator = 0
+
+ // run the game's physics and logic in fixed timesteps (great for physics stability and network determinism)
+ while (Global.accumulator >= FIXED_STEP_MS) {
+ Global.accumulator -= FIXED_STEP_MS
+
+ ECS.fixedUpdate(world, FIXED_STEP_MS)
+
+ ECS.cleanup(world)
+
+ Global.tick++
+ }
+
+ //requestAnimationFrame(simLoop)
+ setTimeout(simLoop, 1000 / 60)
+}
+
+
+main()
+
+
+
+function createWidgetEntity (world) {
+ const w = ECS.createEntity(world)
+ ECS.addComponentToEntity(world, w, 'widget', {
+ frameTTL: 60, // after 60 frames this widget should be removed
+ })
+}
+
+// spawns new widgets entities
+
+function widgetSpawnerSystem (world) {
+
+ const onFixedUpdate = function (dt) {
+ // spawn 1 widget per 60 ticks
+ if (Global.tick % 60 === 0)
+ createWidgetEntity(world, Global.tick)
+
+ // remove any widgets that have expired
+ for (const e of ECS.getEntities(world, WIDGET_QUERY)) {
+ if (e.widget.frameTTL === 0)
+ ECS.removeEntity(world, e)
+ else
+ e.widget.frameTTL--
+ }
+ }
+
+ return { onFixedUpdate }
+}
+
+
+// imagine a system that calculates score based on how many widgets were added/removed on a given frame
+function scoreSystem (world) {
+
+ const result = {
+ count: 0,
+ entries: new Array(100),
+ }
+
+ const onFixedUpdate = function (dt) {
+ ECS.getEntities(world, WIDGET_QUERY, 'added', result)
+ if (result.count)
+ console.log('widgets added:', result.count)
+
+ ECS.getEntities(world, WIDGET_QUERY, 'removed', result)
+ if (result.count)
+ console.log('widgets removed:', result.count)
+
+ }
+
+ return { onFixedUpdate }
+}
+
diff --git a/examples/events/index.html b/examples/events/index.html
new file mode 100644
index 0000000..31db413
--- /dev/null
+++ b/examples/events/index.html
@@ -0,0 +1,62 @@
+
+
+
+
+ ECS example - event handling
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+