Collections of objects that rely on remote data sources. Hides the complexity of fetching and caching data from a remote source.
npm i proxy-collectionsA collection of objects that are not stored in memory, but are fetched from a remote source when needed. This is useful when you have a large collection of objects that you don't want to load all at once.
- lazy: objects are obtained only when needed
- bundles all requests into a single request by the specified delay and chunk size
- cache: fetched objects can be stored in a cache
import { SelectiveProxyMap } from 'proxy-collections';
type Value = {
key: string;
value: string;
};
const collection = new SelectiveProxyMap<string, Value>({
key: 'key',
// function that fetches the data from a remote source given a list of deduplicated grouped keys
handle: async (keys) => {
// here you would fetch the data from a remote source
return keys.map((key) => ({ key, value: `Value for key ${key}` }));
},
// groups all requests in a single request within the last 10ms, but no more than 1000 requests per chunk
delay: 10,
maxChunkSize: 1000,
});
await collection.get('key1'); // Value for key key1
await collection.get(['key2', 'key3']); // Value for key key2You can opt to use a cache to store the fetched objects. The cache must implement type ProxyMapCache. This can be a normal js Map, lru-cache or any similar cache implementation.
import { SelectiveProxyMap } from 'proxy-collections';
type Value = {
key: string;
value: string;
};
const collection = new SelectiveProxyMap<string, Value>({
key: 'key',
handle: async (keys) => {
// here you would fetch the data from a remote source
return keys.map((key) => ({ key, value: `Value for key ${key}` }));
},
cache: new Map(),
});
await collection.get('key1'); // Value for key key1
await collection.get(['key2', 'key3']); // Value for key key2