l1

Game utility: Trigger a function after a set amount of game updates.

---

:sparkles: Features

This library is like setTimeout and setInterval controlled by updates from a game loop.

This way, if you want to something to happen in your game after 60 updates, you just have to write:

``ts
await delay(60)
transitionToNextScreen()
`

In order for this to work, you need to call update on every update. If you are using PixiJS this would mean that somewhere in your code you have to write:

`ts
ticker.add(update)
`

---

API

- delay(duration, options) - Wait a set duration of game updates

`ts
await delay(60)
// Do something once after 60 game updates
`

- forever(callback, interval, options) - Call a function forever, each interval game update

`ts
const interval = 60
forever(() => {
// Do something forever each 60 game updates
}, interval)
`

- every(callback, duration, options) - Call a function every update until duration is reached

`ts
const duration = 60
await l1.every(() => {
// Do something every game update until 60 game updates have passed
}, duration)
`

- update(deltaTime) - Needs to be called on every game update

$3

- getAll() - Get all behaviors

- get(id) - Get one behavior by id

- getByLabel(label) - Get a list of behaviors with a label

- cancel(behavior) - Takes an id or behavior object. Marks the behavior for cancellation. Will be cancelled after all behaviors have been processed in the current game update.

---

Start by calling createInstance.

`ts
const { update, delay } = createInstance()

// Call update every game update
ticker.add(update)
await delay(60)
`

---

:package: Install

`sh
npm install l1
`

---

Getting started - once

TODO: Better examples

`ts
import * as l1 from 'l1'
import * as PIXI from 'pixi.js'

const app = new PIXI.Application()

document.body.appendChild(app.view)

app.ticker.add(l1.update)

app.loader.load(() => {
const square = new PIXI.Sprite(texture)
app.stage.addChild(square)

// Move 1 pixel every 3 ticks
const move = l1.repeat(
() => {
square.x += 1
if (square.x > 500) {
l1.cancel('move')
}
},
3,
{ id: 'move' },
)
})
`

---

Recipes

$3

cancel just marks the behavior for cancellation, but it won't actually be cancelled until the next update

Therefore, you might need to wait a game update before you continue:

`ts
const gameOver = () => {
cancel('gameLoop')
// Ensures that the game doesn't continue until the gameLoop behavior has been deleted
await delay(1)
// Continue
}
`

$3

Use performance.now

`ts
import * as l1 from 'l1'

app.ticker.add((deltaTime) => {
const before = performance.now()

l1.update(deltaTime)

const after = performance.now()
const delta = after - before
})
`

$3

$3

Wrap l1.update with a try catch

`ts
import * as l1 from 'l1'

app.ticker.add((deltaTime) => {
try {
l1.update(deltaTime)
} catch (error) {
console.error(error)
logToExternalService(error)
}
})
`

$3

Use a for..of loop

`ts
for (const item of list) {
doStuff(item)
await delay(50)
}
``