onInput("d", function() {
    getFirst(player).x += 1;
});

Uncaught TypeError: Cannot read properties of undefined (reading 'length') on line ... in column 33. Open the browser console for more information.

getAll(type)
Returns all sprites of the given type. If no bitmap key is specified, it returns all the sprites in the game.

getFirst(type)
Returns the first sprite of a given type. Useful if you know there’s only one of a sprite, such as with a player character.

var gameLoop = setInterval(() => {
  despawnObstacles();
  moveObstacles();
  spawnObstacle();

The Toolkit

Sprig is a tiny construction kit to build tile based games. The games are written in JavaScript. It was made by Hack Club, a global community of teen coders who believe people learn best by making things they care about and sharing them with others. You can watch this video for an introduction to Sprig website.

Run games by hitting the Run button or pressing Shift+Enter.

Getting Help

If this is your first time using Sprig, try playing through the tutorial. From there, we suggest hacking on any of the current games or starting from scratch.

If you ever need help, have ideas, or want to meet other game-makers, join the community in the #sprig channel on the Hack Club Slack.

Level Design

Sprig games are made up of grids of square tiles.

setLegend(bitmaps)

Tell Sprig what types of sprites are available in your game. Bitmap keys must be a single character. We recommend storing character keys in variables.

const player = "p"
const wall = "w"

setLegend(
  [ player, bitmap`...` ],
  [ wall, bitmap`...` ],
)

To create a new bitmap, type

bitmap`.`

Those are backticks! Click on the highlighted “bitmap” button to edit your drawing.

The order of sprite types in your legend also determines the z-order of drawing them. Sprite types that come first are drawn on top.

setBackground(bitmapKey)

Tiles a bitmap as the background of the game:

setBackground(spriteKey)

This only changes the visuals of the game.

setMap(level)

Designing a level is like drawing a bitmap:

map`...`

The characters in the map come from the order of your bitmap legend. Levels don’t have to be kept track of in a legend, you should store them in a variable yourself. You can call setMap to clear the game and load a new level:

const level = map`...`
setMap(level)

You might want to keep track of multiple levels using an array to switch between them mid-game:

const levels = [
  map`...`,
  map`...`,
  // etc.
]
setMap(levels[0])

// Later:
setMap(levels[1])

setSolids(bitmapKey)

Solid sprites can’t overlap with each other. This is useful for creating things like walls:

const player = "p"
const wall = "w"

setSolids([ player, wall ])

setPushables(pushMap)

Use setPushables to make sprites push other sprites around. The sprite on the left will be able to push all sprites listed on the right.

const player = "p"
const block = "b"

setPushables({ 
  [player]: [ block, player ] 
})

Watch out! Make sure everything you pass to setPushables is also marked as a solid or they won’t be pushed around.

width()

Get the width of the current map.

height()

Get the height of the current map.

User Input

Sprig has eight inputs w, a, s, d, i, j, k, l.

Typically w, a, s, d are used as directional controls.

onInput(type, callback)

Do something when the player presses a control:

onInput("d", () => {
  // Move the player one tile to the right
  getFirst(player).x += 1
})

afterInput(callback)

Runs after every input event has finished being handled. Useful for tasks like checking win states:

afterInput(() => {
  if (getAll(block).length > 0) {
    console.log("you win")
  }
})

Sprites and Tiles

Each tile can contain any number of sprites stacked on top of each other.

Sprites contain:

{
  type
  x
  y
}

You can move the sprite by setting x and y.

The bitmapKey can also be changed to update the rendered graphic and collision rules the sprite will follow.

sprite.y += 1
sprite.type = "p"

You can remove a sprite with sprite.remove().

getTile(x, y)

Returns a list of the sprites in the specified tile.

tilesWith(type, …)

Returns a list of the tiles that contain type.

tilesWith(block)

tilesWith accepts multiple sprite types.

tilesWith(block, player, ...)

addSprite(x, y, spriteType)

Creates a new sprite of the given type.

clearTile(x, y)

Removes all sprites from the specified tile.

getAll(type)

Returns all sprites of the given type. If no bitmap key is specified, it returns all the sprites in the game.

getFirst(type)

Returns the first sprite of a given type. Useful if you know there’s only one of a sprite, such as with a player character.

Shortcut for getAll(type)[0].

Text

addText(string, options = { x, y, color })

You can add text with optional x, y, and color.

In Sprig, each color is represented by a single character. Like bitmap and map, you can use the color keyword to pick a color for your text. A preview of your selected color will also show next to the character.

For example:

addText("hello", { 
  x: 10,
  y: 4,
  color: color`3`
})

clearText()

Clears all text on the screen.

Music and Sound Effects

Sprig comes bundled with a built-in sound engine and sequencer! You can use this to write background music, or with a high BPM to make sound effects.

You can create a tune with the tune keyword. As usual, click on the button to open an editor window.

// Create a tune:
const melody = tune`...`

// Play it:
playTune(melody)

// Play it 5 times:
playTune(melody, 5)

// Play it until the heat death of the universe:
const playback = playTune(melody, Infinity)

// Or make it shut up early:
playback.end()

Infinite loop detection

The Sprig editor will automatically insert a heuristic in your for, while and or do-while loops to detect potential infinite loops. Code looking like

while (condition) {
  // do stuff
}

will become

startTime = performance.now()
while (condition) {if (++_loopIt > 2000 && performance.now() - startTime > 1500) throw new RangeError("Potential infinite loop")
  // do stuff
}

Note that all original line numbers in your code will be preserved.