Platform overview

The Platform module is the backbone of elm-ts. It defines the base program() and run() functions which will be extended by more specialized modules. The Elm Architecture is implemented via RxJS Observables.

Added in v0.5.0

Table of contents

• combinators
  • withStop
• constructors
  • program
  • programWithFlags
• model
  • Dispatch (interface)
  • Program (interface)
• utils
  • run

combinators

withStop

Stops the program when signal Observable emits a value.

Signature

export declare function withStop(
  signal: Observable<unknown>
): <Model, Msg>(program: Program<Model, Msg>) => Program<Model, Msg>

Added in v0.5.4

constructors

program

program() is the real core of elm-ts.

When a new Program is defined, a BehaviorSubject is created (because an initial value is needed) that will track every change to the Model and every Cmd executed.

Every time dispatch() is called a new value, computed by the update() function, is added to the the stream.

Signature

export declare function program<Model, Msg>(
  init: [Model, Cmd<Msg>],
  update: (msg: Msg, model: Model) => [Model, Cmd<Msg>],
  subscriptions: (model: Model) => Sub<Msg> = () => none
): Program<Model, Msg>

Added in v0.5.0

programWithFlags

Same as program() but with Flags that can be passed when the Program is created in order to manage initial values.

Signature

export declare function programWithFlags<Flags, Model, Msg>(
  init: (flags: Flags) => [Model, Cmd<Msg>],
  update: (msg: Msg, model: Model) => [Model, Cmd<Msg>],
  subscriptions: (model: Model) => Sub<Msg> = () => none
): (flags: Flags) => Program<Model, Msg>

Added in v0.5.0

model

Dispatch (interface)

Signature

export interface Dispatch<Msg> {
  (msg: Msg): void
}

Added in v0.5.0

Program (interface)

Program is just an object that exposes the underlying streams which compose The Elm Architecture. Even Commands and Subscriptions are expressed as Observables in order to mix them with ease.

Signature

export interface Program<Model, Msg> {
  dispatch: Dispatch<Msg>
  cmd$: Cmd<Msg>
  sub$: Sub<Msg>
  model$: Observable<Model>
}

Added in v0.5.0

utils

run

Runs the Program.

Because the program essentially is an object of streams, “running it” means subscribing to these streams and starting to consume values.

Signature

export declare function run<Model, Msg>(program: Program<Model, Msg>): Observable<Model>

Added in v0.5.0