opencombinejs's Introduction

OpenCombineJS

OpenCombine helpers for JavaScriptKit/WebAssembly APIs. Currently it provides:

A JSScheduler class that implements the Scheduler protocol. This allows you to use time-dependent Combine operators such as measureInterval, debounce, throttle, and timeout in a browser environment.
A TopLevelDecoder implementation on JSValueDecoder.
A publisher property on JSPromise, which converts your JavaScript Promise instances to Combine publishers.

Example

Here's an example of a timer that fetches a UUID from a remote server every second, parses it with JSValueDecoder, and then displays the result as text:

import JavaScriptKit
import OpenCombine
import OpenCombineJS

private let jsFetch = JSObject.global.fetch.function!
func fetch(_ url: String) -> JSPromise {
  JSPromise(jsFetch(url).object!)!
}

let document = JSObject.global.document
var p = document.createElement("p")
_ = document.body.appendChild(p)

var subscription: AnyCancellable?

let timer = JSTimer(millisecondsDelay: 1000, isRepeating: true) {
  subscription = fetch("https://httpbin.org/uuid")
    .publisher
    .flatMap {
      JSPromise($0.json().object!)!.publisher
    }
    .mapError { $0 as Error }
    .map { Result<String, Error>.success($0.uuid.string!) }
    .catch { Just(.failure($0)) }
    .sink {
      let time = JSDate().toLocaleTimeString()
      switch $0 {
      case let .success(uuid):
        p.innerText = .string("At \(time) received uuid \(uuid)")
      case let .failure(error):
        p.innerText = .string("At \(time) received error \(error)")
      }
    }
}

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