https://github.com/basementuniverse/simple-state-machine

Define finite state machines and validate state transitions
https://github.com/basementuniverse/simple-state-machine

Last synced: 23 days ago
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Define finite state machines and validate state transitions

• Host: GitHub
• URL: https://github.com/basementuniverse/simple-state-machine
• Owner: basementuniverse
• License: mit
• Created: 2022-02-18T15:43:45.000Z (almost 3 years ago)
• Default Branch: master
• Last Pushed: 2023-10-25T12:22:26.000Z (about 1 year ago)
• Last Synced: 2024-04-26T04:03:06.820Z (9 months ago)
• Language: TypeScript
• Size: 78.1 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Simple State Machine

Define finite state machines and validate state transitions.

This library doesn't currently provide state-change events or methods for transitioning between states; all it does is provide a format for defining state machines, and a method for checking that a given transition is valid.

## Installation

```

npm install @basementuniverse/simple-state-machine

```

## Usage

```typescript

import {

  StateMachine,

  validateTransition,

} from '@basementuniverse/simple-state-machine';

// Define a finite state machine

const myStateMachine: StateMachine = {

  open: [

    'closedAndUnlocked',

  ],

  closedAndUnlocked: [

    'open',

    'closedAndLocked',

  ],

  closedAndLocked: [

    'closedAndUnlocked',

  ],

};

// Let's validate some transitions...

let result: boolean = false;

// Test #1

result = validateTransition(

  myStateMachine,

  'open',

  'closedAndUnlocked'

);

// result will be true (this is a valid transition)

console.assert(result);

// Test #2

result = validateTransition(

  myStateMachine,

  'closedAndLocked',

  'open'

);

// result will be false (this is not a valid transition)

console.assert(!result);

// Test #3

result = validateTransition(

  myStateMachine,

  'open',

  'closedAndLocked',

  {

    throwErrors: true,

  }

);

// this will throw an error with the message:

// "Invalid state transition: unable to transition from 'open' to 'closedAndLocked'."

// Test #4

result = validateTransition(

  myStateMachine,

  'open',

  'open',

  {

    allowSelfTransition: true,

  }

);

// result will be true (this is a valid transition even though it's not explicitly defined)

console.assert(result);

```

## Options

The `validateTransition` function accepts an optional `options` object as its fourth argument. The following options are available:

| Option | Type | Default | Description |

| --- | --- | --- | --- |

| `allowSelfTransition` | `boolean` | `true` | If `true`, a transition from a state to itself will be considered valid. |

| `throwErrors` | `boolean` | `false` | If `true`, an error will be thrown if the transition is invalid. |