gis-tools-ts/dist/dataStore/kv/file.js

A collection of geospatial tools primarily designed for WGS84, Web Mercator, and S2.

import { S2FileStore } from '../file';
/**
 * # Key-Value File Store
 *
 * ## Description
 * A filesystem key-value store
 *
 * ## Usage
 * ```ts
 * import { FileKV } from 'gis-tools-ts/file';
 *
 * interface Data { name: string };
 *
 * const kv = new FileKV<Data>('./test.kv');
 * // set a key
 * kv.set(1n, { name: 'test' });
 * // get a key
 * const { name } = kv.get(1n); // { name: 'test' }
 * // check if a key exists
 * kv.has(1n); // true
 * // get length of the store
 * console.log(kv.length); // 1
 *
 * // iterate over the store
 * for await (const value of kv) console.log(value);
 *
 * // close the store
 * kv.close();
 * ```
 */
export class FileKV {
    #store;
    /**
     * Builds a new MultiMap file store
     * @param fileName - the path + file name without the extension
     */
    constructor(fileName) {
        this.#store = new S2FileStore(fileName);
    }
    /** @returns - the length of the map */
    get length() {
        return this.#store.length;
    }
    /**
     * Adds a value to the list of values associated with a key
     * @param key - the key
     * @param value - the value to store
     */
    set(key, value) {
        this.#store.set(BigInt(key), value);
    }
    /**
     * Check if the key exists
     * @param key - the key
     * @returns true if the key exists
     */
    async has(key) {
        return await this.#store.has(BigInt(key));
    }
    /**
     * Gets the list of values associated with a key
     * @param key - the key
     * @returns the list of values if the map contains values for the key
     */
    async get(key) {
        const value = await this.#store.get(BigInt(key), 0);
        if (value === undefined)
            return undefined;
        return value[0];
    }
    /**
     * iterate through the values
     * @yields an iterator
     */
    async *values() {
        for await (const { value } of this.#store.entries())
            yield value;
    }
    /**
     * iterate through the values
     * @returns an iterator
     */
    [Symbol.asyncIterator]() {
        return this.values();
    }
    /** Closes the store */
    close() {
        this.#store.close(true);
    }
}
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