20
59%
MIT
This is a rewrite in reasonml of https://github.com/facebook/dataloader/blob/master/src/index.js

bs-dataloader

CircleCI

This is a rewrite of dataloader js lib in reasonml for use with BuckleScript. I have a goal to make it work with native OCaml in the future but I still rely on some JavaScript structures.

Usage

module UserLoaderImpl = {
  type value = user;
  type key = userId;
  /* The batchLoadFun needs to wrap the returned values in Js.Result.t so that we can reject each promise instead of all */
  let batchLoadFun userIds => batchGetUsers userIds;
  let options: options = {batch: true, maxBatchSize: 256, cache: true};
};

module UserLoader = DataLoader.Make UserLoaderImpl;

UserLoader.load "1"
|> Js.Promise.then_ (
  fun user => displayUser user;
  Js.Promise.resolve ()
);

/* elsewhere in your app */

UserLoader.load "2"
|> Js.Promise.then_ (
  fun user => interactWithUser user;
  Js.Promsie.resolve()
);

The example above will load both users at the same time with 1 request. If we later need one of the loaded users again we will get a cached version of the promise, if you need a new version from the server you can clear the key.

updateUser ::userId ::userPatch
|> Js.Promise.then_ (fun _ => Js.Promise.resolve (UserLoader.clear userId))
|> Js.Promise.then_ (fun _ => UserLoader.load "1")
|> Js.Promise.then_ (
  fun user => displayUser user;
  Js.Promise.resolve ()
)

Development

Build

npm run build

Build + Watch

npm run watch

Test

npm run test

Editor

If you use vscode, Press Windows + Shift + B it will build automatically