leaflet-vector-offline/dist/utils.js

Plugin for Leaflet.js that supports offline vector map tiles.

import { getBlobByKey, hasTile } from "leaflet.offline";
export const reflect = (promise) => {
    return promise.then((status) => {
        return { status: "fulfilled", value: status.value };
    }, (error) => {
        return { status: "rejected", reason: error };
    });
};
export const timer = (duration) => {
    return new Promise((resolve) => {
        setTimeout(() => {
            resolve();
        }, duration);
    });
};
/**
 * Fetches the tile image source from the cache if it exists, otherwise fetches
 * it from the online url.
 *
 * This method is from leaflet.offline TileManager but it is not exported.
 *
 * @param key The key of the tile
 * @param url The online url of the tile
 * @returns The url of the tile image source and boolean where if `true`, means
 * the tile was fetched from the URL. If `false`, tile was fetched from cache.
 */
export const getTileImageSource = async (key, url) => {
    const shouldUseUrl = !(await hasTile(key));
    if (shouldUseUrl) {
        return [url, shouldUseUrl];
    }
    const blob = await getBlobByKey(key);
    return [URL.createObjectURL(blob), shouldUseUrl];
};