State Machine

TradeX-chart implements a State Machine for management of some of it’s internal states.

A good deal of inspiration from the excellent XState project for it’s internal finite state machine.

Why reinvent the wheel? While XState does offer a cut down version of it’s library, the aim of TradeX-chart is to have as few external dependencies as possible. Writing a custom state machine also allows for the selective implementation of required features, thus keeping the overhead down.

Accessing the State Machine

You too can leverage the power of a State Machine via the class StateMachine exported by the chart.

import {StateMachine} from "tradex-chart"

Using the State Machine

let stateMachine = new StateMachine(config, context)

@param {Object} config - state machine definition
@param {Object} context - reference to instance that the state machine operates on

The definition context must provide a reference, context.core to the chart instance, as the chart provides the emitter and listener functionality for the events that trigger state transition.

context.core = chart

State Machine Definition (config)

The state machine definition is an object that requires the minimum properties:

id {string} - identifier
initial {string} - initial state
context {Object} - reference to instance that the state machine operates on
states {Object} - states (functions), that will only execute and progress to the next when condition is met.

Optional State Machine Definition Properties

guards {Object} - logical test functions
actions {Object} - functions

Example Definition

const definiton = {
  id: "main",
  initial: "idle",
  context: {},
  states: {

  }
}