Limitless

A small configurable dependency-free event handler that targets ES6.

Installation

yarn add limitlessjs

npm install --save limitlessjs

Usage

import {Limitless} from 'limitlessjs'

const limitless = new Limitless()
 // or
const limitless = Limitless.create()

Upgrading to 2.x

Breaking changes

• This library has been converted to Typescript, Limitless is a class (new is required)
• RunHandlers, TriggerHandlers, and ArgumentHandlers now accept an object instead of positional arguments.
• Event Modifiers have been removed, use Array.prototype and #flat(Infinity) on the Event instead.
• Limitless#forFile and defaultFileHandler have been removed, here's the equivalent if you need a replacement.

const contents = fs.readFileSync(filename, 'utf8')
const {config = {}, jobs = [], pipeline = [], ...rest} = JSON.parse(contents)
jobs.forEach(core.withJobDefinition)
core.withConfig(config)
pipeline.forEach(core.withPipeline)

Components

• Events
• Job Definitions
• Run Handlers
• Triggers & Trigger Handlers
• Arguments & Argument Handlers
• Config
• Pipeline

Events

The input to Limitless, one or more passed into #process

    EventHandler.create()
      .withJobDefinition({runType: '__identity'})
      .process(1, 2, 3, 4) // Output: [1, 2, 3, 4]

Job Definitions

Core building block of Limitless that defines what can happen when an Event is received.

    // JobDefinition
    { 
        runType: string, 
        name: string, 
        triggers: [Trigger], 
        arguments: [Argument], 
        ...rest 
    } 

• runType (required) - the name of the RunHandler that should be called to process this job
• name (required, defaults to job-[number], e.g. job-0) - the name of this job
• triggers (optional, see Triggers) - What triggers this job to run
• arguments (optional, defaults to event) - How should event be passed to job runner
• add any additional fields that would be useful for your Run Handlers

Run Handlers

Run a job definition, if triggered.

    // Run Handler
    (
        args: [], 
        job: JobDefinition, 
        name: string, 
        pastResults: [], 
        event: any, 
        config: Config
    ) => any

• argsFromEvent - result of applying Argument Handlers on the Event
• job - the full job definition
• name - the name of the job (e.g job-0)
• pastResults - anything that has already been processed
• event - the event that was passed into Argument Handlers

Built In Run Handlers

• __identity - returns input
• __toJson - converts input to json string
• __fromJson - converts string to json object

Triggers & Trigger Handlers

Decides when a job should run. By default if no trigger handlers are registered then all jobs are run, if any trigger handlers have been registered then only the jobs with matching triggers will run.

Arguments

• type (required) - the name of the TriggerHandler that should be called to process this trigger
• definition (optional, defaults to undefined) - additional config required by Trigger

Trigger Handlers

    // Trigger Handler
    ({
        definition: any,
        event: any, 
        handlers: Object
    }) => boolean 

Built In Trigger Handlers

• __all - Requires all triggers to match
• __any - Requires any triggers to match, default behavior
• __not - Inverts the result of trigger

Arguments

The object passed into a RunHandler, the result of applying Argument Handlers on the event

Argument Handler

    // Argument Handler
    ({
        event: any, 
        definition: Object
    }) => any

Built In Argument Handlers

• __identity - returns input
• __toJson - converts input to json string
• __fromJson - converts string to json object
• __fromRegex - definition is a regular expression
• __keyword - definition is an object of keys to argument handlers
• __positional - definition is an array of argument handlers
• __env - definition is the name of the environment variable to read
• __value - use the value from definition

Config

Shared object passed into Run Handlers

Pipeline

Define sets of jobs that should run into each other. e.g. job3(job2(job1(event)))

Arguments

• triggers (required) - the names of jobs that start this pipeline
• steps (required) - the names of jobs that run, in order, in this pipeline