TasksML

TasksML offers a system similar to Promises, Tasks, etc. We call them tasks. Like promises, tasks represent the result stemming from the success or failure of an asynchronous call (Input/output). Tasks are lazy.

(Documentation is a work in progress) Make sure you have bs-platform >= 4.0.18. Then install with npm: npm install --save tasks-ml

Then add "tasks-ml" to your bsconfig.json dev dependencies:

{ ... "bs-dependencies": [ "tasks-ml" ] }

Usage

Open Module

TasksML is written as modular reasonML. In reasonML modules are like mini files! They can contain type definitions, let bindings, nested modules, etc. A module's contents (including types!) can be accessed much like a record's, using the . notation. This demonstrates modules' utility for namespacing. Constantly referring to a value/type in a module can be tedious. Instead, we can "open" a module and refer to its contents without always prepending them with the module's name.

Open Task
let timeout = value => Task((rej, res) => {
  let timer = Js.Global.setTimeout(() => {res(value)}, 1000)
  Cancel(() => Js.Global.clearTimeout(timer))
})

Creating Tasks

Tasks

Creates a tasks with the given computation. A computation is a function which takes two callbacks. Both are continuations for the computation. The first is reject, commonly abbreviated to rej; The second is resolve, or res. When the computation is finished (possibly asynchronously) it may call the appropriate continuation with a failure or success value. Additionally, the computation may return a nullary function containing cancellation logic. See Cancellation.

let timeout = value => Task((rej, res) => {
  let timer = Js.Global.setTimeout(() => {res(value)}, 1000)
  Cancel(() => Js.Global.clearTimeout(timer))
})

Reject

Creates a task which immediately rejects with the given value.

let sampleReject = Task.reject("Sample reject text!");
sampleReject |> run (
    status  =>
        switch (status) {
        | Rejection(e) => Js.log("Rejection Case", e)
        | Success(s) => Js.log("This will never run", s) //this sample immediately rejects
    }
);
//! "Rejection Case! Sample reject text!"

Identity

Creates a task which immediately resolves with the given value

let sampleReject = Task.reject("Sample resolve text!");
sampleReject |> run (
    status  =>
        switch (status) {
        | Rejection(e) => Js.log("This will never run", e) //this sample immediately resolves
        | Success(s) => Js.log("Success Case", s)
    }
);
//! "Success Case! Sample resolve text!"

Note: The Compiled Javascript is located in the lib/js folder