leap

Simple flow-control tool for coffee-script. It makes async coding much easier.

Examples

  leap ->
    #first async function
  , ->
    #second async function
  , ->
    # all functions are executed in parallel

  leap ->
    # do something async
    @next results
  .then (res) ->
    # do something async with results
    async_function res, @
  .and (res) ->
    # do something else with it in parallel
    another_async_function res, @
  .then ([first_res, second_res]) ->
    # use data from async results of previous step

  leap ->
    async_function ["Kinks", "Beatles", "United States of America"], @
  .then.map (rockband) ->
    async_function "The #{rockband}", @
  .then (bands) ->
    bands.should.be.deep.equal [
      "The Kinks"
      "The Beatles"
      "The United States of America"
    ]
  .rescue (err) ->
    #handle all async errors in one place

Usage

• install via npm

  npm install leap

• require in your code

  leap = require 'leap'

API

• leap(functions...)

  Run one ore more functions as a first step of sequence. All functions are called with callback as first parameter. Also, callback is a context of all functions.

  leap (callback) ->
    fs.readFile 'file', callback

  is the same as

  leap ->
    fs.readFile 'file', @

• .then(functions...)

  Add one o more functions to be executed after previous step. All functions are called with results of previous step as first parameter, callback as second parameter. Also, callback is a context.

  leap ->
    fs.readFile 'file', @
  .then (content) ->
    db.create content, @
  , (content) ->
    some_api_request.find content, @
  .then ([db_entry, api_response]) ->
    #

• .and(functions...)

  Add functions to current step. All functions get results from previous step as first parameter. Also, callback is a context and second parameter.

  leap ->
    model.countLikes user, @
  .and  ->
    model.countViews user, @
  .then ([likes, views]) ->
    addToResponse likes, views
    do @
  .and ([likes, views]) ->
    saveToCache user, likes, views, @

• .rescue(handler)

  All errors stops execution of a flow and processed by handler. Error is passed by first argument

    leap ->
      fs.readFile 'test1', @
    , ->
      fs.readFile 'test2', @
    .rescue (err) ->
      console.log err

• callbacks: @ and @next

  Will be documented soon. see tests.

• leap.map(iterator)

• .and.map(iterator)

• .then.map(iterator)

  Will be documented soon. see tests.

• leap.reduce(iterator)

• .and.reduce(iterator)

• .then.reduce(iterator)

  Will be documented soon. see tests.

• leap.filter(iterator)

• .and.filter(iterator)

• .then.filter(iterator)

  Will be documented soon. see tests.

• leap.reject(iterator)

• .and.reject(iterator)

• .then.reject(iterator)

  Will be documented soon. see tests.

Inspired by

• invoke.js by Steve Lloyd
• first by Daniel Baulig
• async.js by Caolan McMahon

Testing

$ npm test

License

MIT