Flow - a Seneca plugin

• Lead Maintainer: Georgi Griffiths
• Node: 4.x, 6.x

Why write code when you can write messages

The plugin enables actions to contain actions with can be used to format properties for the action.

• Control flow
• Output transforms using lodash
• Templating

Features

All messages can have the following properties:

• if$: string with condition to be evaluated in order to run the actions
• until$: string with condition to be evaluated in order to continue
• wait$: milliseconds to wait before retry action to check until$
• pause$: milliseconds to pause after action has completed
• $$'anyproperty': object each property is a action which is preloaded to use in templates
• $'anyproperty': object will execute message and set action property without $. Nested properties must prefix $ for each parent.
• out$: object/array of actions which run using Waterfall. Fixed value which can use template functions.
• key$: string for the key to store the message data. Used in sequences
• exit$: string condition for exit. Used in sequences

Templates

Each of the actions property values can contain the following:

• $: using only the $ will assign the input data of the same property
  • input { x:10 } action { x:'$' } set action { x:10 }
• $*: assigns all input data
  • input { x:10 } action { x:'$*' } set action { x : { x:10 } }
• <%= %>: lodash templating
  • input { x:10, y:20, msg:'hello' } action { alert:'<%= $.msg %> x = <%= $.x %> y = <%= $.y %>' } set action { alert : 'hello x = 10 y = 20' }
• If none of the above but contains $ the expression will be evaluated
  • input { x:10 } action { y:'$.x', z:'$.x * $.x' } set action { y : 10, z : 100 }

Input data is created and assigned to $ from $$'anyproperty' and data from the previous action in sequences.

Sequence

Properties:

• sequence: (required) array of actions
  • exit$: (optional) string condition for exit on each action. Run after each action and can use :
    • '$' which will be populated with results set via key$ and 'in' will be set to the previous action result
    • 'out' which will contain the result of the action
• merge: (optional) boolean Merge result data when set via key$ otherwise overwrite
• data: (optional) object to be passed to each action for templating
• extend: (optional) object to extend each action
• in: (optional) set in data for start of sequence

Iterate

Properties:

• iterate: (required) object action to use to iterate
• with: (with or times required) array of objects to to iterator as "in" property
• times: (with or times required) integer number of times to iterate
• exit: (optional) string condition for exit. Run after each action and can use :
  • '$.in' will be set to the current 'with' data.
  • 'index' current index
  • 'out' which will contain the result of the action
• series: (optional) boolean force run in series
• data: (optional) object to be passed to each iteration for templating
• extend: (optional) object to extend each action

Parallel

Properties:

• parallel: (required) array actions to execute
• merge: (optional) boolean merge results of actions

Waterfall

Properties:

• waterfall: (required) array actions to execute. Actions must accept 'in' property
• in: (optional) data to pass to first item

Map

Properties:

• map: (required) object action to run for each
• in: (required) array

_ : Lodash

This is a waterfall compatible function to transform action results via the out$ property

Properties:

• _: (required) string lodash function to call
• in: (required) data to pass to first argument
• args: (optional) arguments for function
• select: (optional) property to operate on

Install

npm install seneca-flow

Testing

npm test

Releases

• 0.0.1:
  • initial
• 1.0.1:
  • use seneca-parambulator
  • rename each to map
  • add coveralls
  • update code style for linting
• 1.0.2
  • update dependencies

License

Copyright (c) 2016 Georgi Griffiths; Licensed under MIT.