flat-flow

Summary

Tiny flow with conditional branching.

Installation

npm install flat-flow --save

Usage

{ flow } = require 'flat-flow'

# This is how to use me.
flow [

  # 1-arity functions are called and result from (err, result) merged with locals.
  # If you pass an error as first arg, the whole flow will be finished, see the bottom.
  (done) ->
    done null, { a: 1, b: 2 }

  # 0-arity functions that return boolean manage the flow; false will all calls until true is found in 0-arity.
  -> false

  # Will be skipped.
  (done) ->
    done null, { c: 3 }

  # Resume flow. You have access to locals merged before.
  -> @a is 1

  # Will be called because we resumed the flow above.
  (done) ->
    done null, { e: @a + @b }

  # 2-arity functions allows you to refer to locals if you don't want to bind all nested functions.
  (done, { e }) ->
    process.nextTick ->
      process.nextTick ->
        done null, { f: e + 1 }

  # ...otherwise you can use locals directly
  (done) ->
    process.nextTick => # fat
      process.nextTick => # fat
        done null, { g: @f + 1 }

], (err, { e, f }) -> # final callback, always called.
  assert.ifError err

  # Locals are here as well.
  assert.equal @a, 1
  assert.equal @b, 2
  assert.equal @c, undefined
  assert.equal @d, undefined

  # Or you can access them from optional 2nd argument.
  assert.equal e, 3
  assert.equal f, 4

  assert.equal @g, 5