Helpers for core.async

Helper pack for core.async with focus on error propagation, see docs for more and examples.

Features

• error propagation by climbing up the go block stack via go / go-loop / map / reduce / <! / <? and more (all functions within this package propagate errors)
• promise channel helpers
  • to ensure promise-chan via promise-go ->promise-chan and its behavior
  • to create promise-chan via promise-chan function with resolve and reject handlers
  • conversion from channel to promise and vice versa via c->p, p->c and <!p
• helpers to handle callback based functions by conversion into channel via cb->c and <cb!

Getting started

Get it / add dependency

Add the following dependency to your project.clj:

Usage

Pay attention mixing up error propagation functions of this library and clojure.core.async functions. clojure.core.async function do not propagate errors. E.g. using a core.async go-block within a error propagation go-block stack will break error propagation. So do not mix it up!

(ns your-project
  #?(:clj
     (:require
      [clojure.core.async :refer [timeout]]
      [jtk-dvlp.async :as a])

     :cljs
     (:require
      [cljs.core.async :refer [timeout]]
      [jtk-dvlp.async :as a]))

  #?(:clj
     (:import
      [clojure.lang ExceptionInfo]))

  ,,,)


(defn <do-some-async-stuff
  [& args]
  (a/go
    (a/<! (timeout 1000))
    (let [result
          {:call-args args}]

      (println result)
      result)))

(defn <fail-during-some-async-stuff
  [& args]
  (a/go
    (a/<! (timeout 1000))
    (->> {:call-args args}
         (ex-info "you got a bug")
         (throw))))

(comment
  (a/go
    (try
      (let [a
            (a/<! (<do-some-async-stuff :a))

            b
            (a/<! (<fail-during-some-async-stuff :b))

            c
            (a/<! (<do-some-async-stuff :c))]

        (println [a b c]))

      (catch ExceptionInfo e
        (println "there is an error" e))))

  ,,,)

Appendix

I´d be thankful to receive patches, comments and constructive criticism.

Hope the package is useful :-)