--- title: "Source | JavaScript maps SDK" description: "Documentation for MapTiler SDK" --- > For AI agents: a documentation index is available at [/llms.txt](https://docs.maptiler.com/llms.txt). Markdown versions of all pages are available by appending .md to any URL. # Interface Source The `Source` interface must be implemented by each source type, including "core" types (`vector`, `raster`, `video`, etc.) and all custom, third-party types. **Event** `data` - Fired with `{dataType: 'source', sourceDataType: 'metadata'}` to indicate that any necessary metadata has been loaded so that it's okay to call `loadTile`; and with `{dataType: 'source', sourceDataType: 'content'}` to indicate that the source data has changed, so that any current caches should be flushed. interface Source {     [attribution](#attribution)?: string;     [calculateTileZoom](#calculatetilezoom)?: [CalculateTileZoomFunction](https://docs.maptiler.com/sdk-js/api-reference/types/CalculateTileZoomFunction/);     [id](#id): string;     [isTileClipped](#istileclipped)?: boolean;     [maxzoom](#maxzoom): number;     [minzoom](#minzoom): number;     [reparseOverscaled](#reparseoverscaled)?: boolean;     [roundZoom](#roundzoom)?: boolean;     [tileID](#tileid)?: [CanonicalTileID](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.CanonicalTileID/);     [tileSize](#tilesize): number;     [type](#type): string;     [vectorLayerIds](#vectorlayerids)?: string\[\];     [abortTile](#aborttile-1)?(tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/)): Promise;     [fire](#fire-1)(event: [Event](https://docs.maptiler.com/sdk-js/api-reference/classes/Event/)): unknown;     [hasTile](#hastile-1)?(tileID: [OverscaledTileID](https://docs.maptiler.com/sdk-js/api-reference/classes/OverscaledTileID/)): boolean;     [hasTransition](#hastransition-1)(): boolean;     [loaded](#loaded-1)(): boolean;     [loadTile](#loadtile-1)(tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/)): Promise;     [onAdd](#onadd-1)?(map: [MapLibreMap](https://docs.maptiler.com/sdk-js/api-reference/classes/MapLibreMap/)): void;     [onRemove](#onremove-1)?(map: [MapLibreMap](https://docs.maptiler.com/sdk-js/api-reference/classes/MapLibreMap/)): void;     [prepare](#prepare-1)?(): void;     [serialize](#serialize-1)(): any;     [shouldReloadTile](#shouldreloadtile-1)?(         tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/),         options: [GeoJSONSourceShouldReloadTileOptions](https://docs.maptiler.com/sdk-js/api-reference/types/Externals.GeoJSONSourceShouldReloadTileOptions/),     ): boolean;     [unloadTile](#unloadtile-1)?(tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/)): Promise; } #### Implemented by - [GeoJSONSource](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.GeoJSONSource/) - [ImageSource](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.ImageSource/) - [RasterDEMTileSource](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.RasterDEMTileSource/) - [RasterTileSource](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.RasterTileSource/) - [VectorTileSource](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.VectorTileSource/) ##### Index ### Properties[](#properties) [attribution?](#attribution) [calculateTileZoom?](#calculatetilezoom) [id](#id) [isTileClipped?](#istileclipped) [maxzoom](#maxzoom) [minzoom](#minzoom) [reparseOverscaled?](#reparseoverscaled) [roundZoom?](#roundzoom) [tileID?](#tileid) [tileSize](#tilesize) [type](#type) [vectorLayerIds?](#vectorlayerids) ### Methods[](#methods) [abortTile?](#aborttile) [fire](#fire) [hasTile?](#hastile) [hasTransition](#hastransition) [loaded](#loaded) [loadTile](#loadtile) [onAdd?](#onadd) [onRemove?](#onremove) [prepare?](#prepare) [serialize](#serialize) [shouldReloadTile?](#shouldreloadtile) [unloadTile?](#unloadtile) ## Properties[](#properties-1) ### `Optional`attribution[](#attribution) attribution?: string The attribution for the source. ### `Optional`calculateTileZoom[](#calculatetilezoom) calculateTileZoom?: [CalculateTileZoomFunction](https://docs.maptiler.com/sdk-js/api-reference/types/CalculateTileZoomFunction/) Optional function to redefine how tiles are loaded at high pitch angles. ### id[](#id) id: string The id for the source. Must not be used by any existing source. ### `Optional`isTileClipped[](#istileclipped) isTileClipped?: boolean `false` if tiles can be drawn outside their boundaries, `true` if they cannot. ### maxzoom[](#maxzoom) maxzoom: number The maximum zoom level for the source. ### minzoom[](#minzoom) minzoom: number The minimum zoom level for the source. ### `Optional`reparseOverscaled[](#reparseoverscaled) reparseOverscaled?: boolean `true` if tiles should be sent back to the worker for each overzoomed zoom level, `false` if not. ### `Optional`roundZoom[](#roundzoom) roundZoom?: boolean `true` if zoom levels are rounded to the nearest integer in the source data, `false` if they are floor-ed to the nearest integer. ### `Optional`tileID[](#tileid) tileID?: [CanonicalTileID](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.CanonicalTileID/) ### tileSize[](#tilesize) tileSize: number The tile size for the source. ### `Readonly`type[](#type) type: string ### `Optional`vectorLayerIds[](#vectorlayerids) vectorLayerIds?: string\[\] ## Methods[](#methods-1) ### `Optional`abortTile[](#aborttile) - abortTile?(tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/)): Promise[](#aborttile-1) Allows to abort a tile loading. #### Parameters - tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/) The tile to abort #### Returns Promise ### fire[](#fire) - fire(event: [Event](https://docs.maptiler.com/sdk-js/api-reference/classes/Event/)): unknown[](#fire-1) An ability to fire an event to all the listeners, see [Evented](https://docs.maptiler.com/sdk-js/api-reference/classes/Externals.Evented/) #### Parameters - event: [Event](https://docs.maptiler.com/sdk-js/api-reference/classes/Event/) The event to fire #### Returns unknown ### `Optional`hasTile[](#hastile) - hasTile?(tileID: [OverscaledTileID](https://docs.maptiler.com/sdk-js/api-reference/classes/OverscaledTileID/)): boolean[](#hastile-1) True is the tile is part of the source, false otherwise. #### Parameters - tileID: [OverscaledTileID](https://docs.maptiler.com/sdk-js/api-reference/classes/OverscaledTileID/) The tile ID #### Returns boolean ### hasTransition[](#hastransition) - hasTransition(): boolean[](#hastransition-1) True if the source has transition, false otherwise. #### Returns boolean ### loaded[](#loaded) - loaded(): boolean[](#loaded-1) True if the source is loaded, false otherwise. #### Returns boolean ### loadTile[](#loadtile) - loadTile(tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/)): Promise[](#loadtile-1) This method does the heavy lifting of loading a tile. In most cases it will defer the work to the relevant worker source. #### Parameters - tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/) The tile to load #### Returns Promise ### `Optional`onAdd[](#onadd) - onAdd?(map: [MapLibreMap](https://docs.maptiler.com/sdk-js/api-reference/classes/MapLibreMap/)): void[](#onadd-1) This method is called when the source is added to the map. #### Parameters - map: [MapLibreMap](https://docs.maptiler.com/sdk-js/api-reference/classes/MapLibreMap/) The map instance #### Returns void ### `Optional`onRemove[](#onremove) - onRemove?(map: [MapLibreMap](https://docs.maptiler.com/sdk-js/api-reference/classes/MapLibreMap/)): void[](#onremove-1) This method is called when the source is removed from the map. #### Parameters - map: [MapLibreMap](https://docs.maptiler.com/sdk-js/api-reference/classes/MapLibreMap/) The map instance #### Returns void ### `Optional`prepare[](#prepare) - prepare?(): void[](#prepare-1) Allows to execute a prepare step before the source is used. #### Returns void ### serialize[](#serialize) - serialize(): any[](#serialize-1) #### Returns any A plain (stringifiable) JS object representing the current state of the source. Creating a source using the returned object as the `options` should result in a Source that is equivalent to this one. ### `Optional`shouldReloadTile[](#shouldreloadtile) - shouldReloadTile?(     tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/),     options: [GeoJSONSourceShouldReloadTileOptions](https://docs.maptiler.com/sdk-js/api-reference/types/Externals.GeoJSONSourceShouldReloadTileOptions/), ): boolean[](#shouldreloadtile-1) Optional function to determine whether a tile should be reloaded, given a set of options associated with a `MapSourceDataChangedEvent`. #### Parameters - tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/) - options: [GeoJSONSourceShouldReloadTileOptions](https://docs.maptiler.com/sdk-js/api-reference/types/Externals.GeoJSONSourceShouldReloadTileOptions/) #### Returns boolean #### Internal[](#internal) ### `Optional`unloadTile[](#unloadtile) - unloadTile?(tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/)): Promise[](#unloadtile-1) Allows to unload a tile. #### Parameters - tile: [Tile](https://docs.maptiler.com/sdk-js/api-reference/classes/Tile/) The tile to unload #### Returns Promise