import { Document } from "@langchain/core/documents"; import { BaseStore } from "@langchain/core/stores"; /** * Class that provides a layer of abstraction over the base storage, * allowing for the encoding and decoding of keys and values. It extends * the BaseStore class. */ // eslint-disable-next-line @typescript-eslint/no-explicit-any export class EncoderBackedStore extends BaseStore { constructor(fields) { super(fields); Object.defineProperty(this, "lc_namespace", { enumerable: true, configurable: true, writable: true, value: ["langchain", "storage"] }); Object.defineProperty(this, "store", { enumerable: true, configurable: true, writable: true, value: void 0 }); Object.defineProperty(this, "keyEncoder", { enumerable: true, configurable: true, writable: true, value: void 0 }); Object.defineProperty(this, "valueSerializer", { enumerable: true, configurable: true, writable: true, value: void 0 }); Object.defineProperty(this, "valueDeserializer", { enumerable: true, configurable: true, writable: true, value: void 0 }); this.store = fields.store; this.keyEncoder = fields.keyEncoder; this.valueSerializer = fields.valueSerializer; this.valueDeserializer = fields.valueDeserializer; } /** * Method to get multiple keys at once. It works with the encoded keys and * serialized values. * @param keys Array of keys to get * @returns Promise that resolves with an array of values or undefined for each key */ async mget(keys) { const encodedKeys = keys.map(this.keyEncoder); const values = await this.store.mget(encodedKeys); return values.map((value) => { if (value === undefined) { return undefined; } return this.valueDeserializer(value); }); } /** * Method to set multiple keys at once. It works with the encoded keys and * serialized values. * @param keyValuePairs Array of key-value pairs to set * @returns Promise that resolves when the operation is complete */ async mset(keyValuePairs) { const encodedPairs = keyValuePairs.map(([key, value]) => [this.keyEncoder(key), this.valueSerializer(value)]); return this.store.mset(encodedPairs); } /** * Method to delete multiple keys at once. It works with the encoded keys. * @param keys Array of keys to delete * @returns Promise that resolves when the operation is complete */ async mdelete(keys) { const encodedKeys = keys.map(this.keyEncoder); return this.store.mdelete(encodedKeys); } /** * Method to yield keys. It works with the encoded keys. * @param prefix Optional prefix to filter keys * @returns AsyncGenerator that yields keys */ async *yieldKeys(prefix) { yield* this.store.yieldKeys(prefix); } } export function createDocumentStoreFromByteStore(store) { const encoder = new TextEncoder(); const decoder = new TextDecoder(); return new EncoderBackedStore({ store, keyEncoder: (key) => key, valueSerializer: (doc) => encoder.encode(JSON.stringify({ pageContent: doc.pageContent, metadata: doc.metadata })), valueDeserializer: (bytes) => new Document(JSON.parse(decoder.decode(bytes))), }); }