gis-tools-ts
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A collection of geospatial tools primarily designed for WGS84, Web Mercator, and S2.
97 lines • 2.34 kB
JavaScript
import { compareIDs } from '../..';
/**
* # MultiMap Store
*
* ## Description
* A local multimap store
*
* ## Usage
* ```ts
* import { MultiMap } from 'gis-tools-ts';
*
* interface Data { name: string };
*
* const mm = new MultiMap<Data>();
* // set a key
* mm.set(1n, { name: 'test' });
* mm.set(1n, { name: 'test2' });
* // get a key
* const { name } = mm.get(1n); // [{ name: 'test' }, { name: 'test2' }]
* // check if a key exists
* mm.has(1n); // true
* // get length of the store
* console.log(mm.length); // 2
*
* // iterate over the store
* for await (const entry of mm) console.log(entry);
*
* // close the store
* mm.close();
* ```
*/
export class MultiMap {
#store;
#count = 0;
/** Builds a new MultiMap */
constructor() {
this.#store = new Map();
}
/** @returns - the length of the map */
get length() {
return this.#count;
}
/**
* 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) {
const list = this.get(key);
if (list === undefined) {
this.#store.set(BigInt(key), [value]);
}
else {
list.push(value);
}
this.#count++;
}
/**
* Check if the key exists
* @param key - the key
* @returns true if the key exists
*/
has(key) {
return 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
*/
get(key) {
return this.#store.get(BigInt(key));
}
/**
* iterate through the values
* @yields - The values in the store
*/
async *entries() {
const entries = Array.from(this.#store.entries()).map(([id, value]) => [id, value]);
entries.sort((a, b) => compareIDs(a[0], b[0]));
for (const [key, value] of entries) {
yield { key, value };
}
}
/**
* iterate through the values
* @returns - an iterator
*/
[Symbol.asyncIterator]() {
return this.entries();
}
/** Closes the store */
close() {
this.#store.clear();
}
}
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