langchain.js
    Preparing search index...

    Class LocalFileStore

    File system implementation of the BaseStore using a dictionary. Used for storing key-value pairs in the file system.

    const store = await LocalFileStore.fromPath("./messages");
    await store.mset(
      Array.from({ length: 5 }).map((_, index) => [
        `message:id:${index}`,
        new TextEncoder().encode(
          JSON.stringify(
            index % 2 === 0
              ? new AIMessage("ai stuff...")
              : new HumanMessage("human stuff..."),
          ),
        ),
      ]),
    );
    const retrievedMessages = await store.mget(["message:id:0", "message:id:1"]);
    console.log(retrievedMessages.map((v) => new TextDecoder().decode(v)));
    for await (const key of store.yieldKeys("message:id:")) {
      await store.mdelete([key]);
    }

    Security Notice This file store can alter any text file in the provided directory and any subfolders. Make sure that the path you specify when initializing the store is free of other files.

    Hierarchy (View Summary)

    Index

    Constructors

    constructor

    Properties

    lc_namespace rootPath

    Methods

    mdelete mget mset yieldKeys fromPath

    Constructors

    • Parameters

      • fields: { rootPath: string }

      Returns LocalFileStore

    Properties

    lc_namespace: string[] = ...
    rootPath: string

    Methods

    • Deletes the given keys and their associated values from the store.

      Parameters

      • keys: string[]

        Keys to delete from the store.

      Returns Promise<void>

      Promise that resolves when all keys have been deleted.

    • Retrieves the values associated with the given keys from the store.

      Parameters

      • keys: string[]

        Keys to retrieve values for.

      Returns Promise<(undefined | Uint8Array<ArrayBufferLike>)[]>

      Array of values associated with the given keys.

    • Sets the values for the given keys in the store.

      Parameters

      • keyValuePairs: [string, Uint8Array<ArrayBufferLike>][]

        Array of key-value pairs to set in the store.

      Returns Promise<void>

      Promise that resolves when all key-value pairs have been set.

    • Asynchronous generator that yields keys from the store. If a prefix is provided, it only yields keys that start with the prefix.

      Parameters

      • Optionalprefix: string

        Optional prefix to filter keys.

      Returns AsyncGenerator<string>

      AsyncGenerator that yields keys from the store.

    • Static method for initializing the class. Preforms a check to see if the directory exists, and if not, creates it.

      Parameters

      • rootPath: string

      Returns Promise<LocalFileStore>

      Promise that resolves to an instance of the class.

    Settings

    Member Visibility

    On This Page

    Constructors
    Properties
    Methods