s2maps-gpu/dist/workers/source/jsonSource.js

S2 Maps GPU - An open source, high-performance, and GPU-accelerated map engine for rendering large-scale, interactive maps.

import Source from './source.js';
import { TileStore } from 'gis-tools/index.js';
import { WMPointCluster } from './pointCluster/index.js';
/**
 * # JSON Source
 *
 * ## Description
 * A source that is a json file that contains geojson or s2json data.
 *
 * The json can be stored as a tile store or a point cluster.
 */
export default class JSONSource extends Source {
    json;
    /**
     * @param mapID - the id of the map to build for
     * @param metadata - the metadata for the source
     */
    async build(mapID, metadata) {
        const json = metadata?.data ?? (await this._fetch(`${this.path}`, mapID, true));
        if (json === undefined) {
            this.active = false;
            console.error(`FAILED TO extrapolate ${this.path} json data`);
            return;
        }
        if (metadata?.cluster === true) {
            this.json = new WMPointCluster(metadata);
            this.json.addManyPoints(json);
            this.json.cluster();
        }
        else {
            // use the projection from the style
            this.json = new TileStore(json, {
                ...metadata,
                projection: this.projection === 'S2' ? 'S2' : 'WG',
            });
        }
        const { projection, minzoom, maxzoom, faces } = this.json;
        this._buildMetadata({
            type: 'vector',
            minzoom,
            maxzoom,
            faces: [...faces],
            layers: { default: { minzoom, maxzoom, drawTypes: [], shape: {} } },
            extension: projection === 'S2' ? 's2json' : 'geojson',
            attributions: 'attributions' in json ? json.attributions : {},
        }, mapID);
    }
    /**
     * Fetch a tile
     * @param mapID - the id of the map requesting data
     * @param tile - the tile request
     */
    async _tileRequest(mapID, tile) {
        const { name, json, session, textEncoder } = this;
        const { id, face } = tile;
        if (json.faces.has(face)) {
            // grab the data
            const vectorTile = json.getTile(id);
            // prep worker
            const worker = session.requestWorker();
            if (Object.values(vectorTile?.layers ?? {}).length === 0) {
                this._flush(mapID, tile, name);
                return;
            }
            // compress
            const data = await textEncoder.encode(JSON.stringify(vectorTile)).buffer;
            // send off
            worker.postMessage({ mapID, type: 'jsondata', tile, sourceName: name, data }, [data]);
        }
        else {
            this._flush(mapID, tile, name);
        }
    }
}