Built for Branching

bBot builds better bots because it's built for branching. Bleep bloop.

-- bBot ©️ 2018

A branch is a piece of logic that applies when input is matched. It may trigger a response or data processing, possibly even creating more branches.

Each branch has a matcher and a callback and may have other behaviours configured by an options object. Branches are declared from a path, to be processed against all incoming messages, or only following another branch.

There are different types of branch for matching different types of input, but all callbacks follow the same pattern, which receives the state b argument providing access to conversational context and utilities to take action.

When messages are received, branches are processed and callbacks for a matching branch are called. Normally processing ends when a matching branch is found, but branch options can set a force attribute so they will always be processed, regardless if another branch has already matched.

A path is parent to a collection of branches. Path methods provide helpers for adding different types of branches:

  • text uses basic regular expression matching
  • direct as above, yet only if prefixed with the bot's name
  • custom accepts a custom matching function
  • enter matches on users entering a chat room
  • leave matches on users leaving a chat room
  • topic matches on users changing the topic of a room
  • NLU uses criteria for natural language understanding
  • directNLU as above, yet only if prefixed with the bot's name
  • customNLU accepts a custom NLU result matching function
  • catchAll matches only when nothing else has

Branch Matching

When processing incoming messages, each branch's matching function is applied. If the function returns a truthy value (e.g. a regex match object), then the callback is fired.

Text branches accept semantic attributes handled by our conditions module, such as { contains: 'hello' } or { is: 'cancel' }. For more advanced text matching you can use regular expressions instead.

Read the Conditions docs for details of the available attributes.

NLU branches accept a standard criteria object, defining the conditions that should be met in the result that is returned from natural language processing.

Read the NLU doc for more details on using NLU criteria.

Branch Callbacks

All branch callbacks receive the same single argument, the bot state object. For brevity we call it b. From it you can access the bot, the message, it's match result. The state instance also has helpers for responding. Basically everything you need to take action.

Callbacks can be asynchronous and processing will await their resolution, allowing great flexibility for building responses or processing logic that might depend on external requests or data querying.

The "Global" Path

Paths give us a way of isolating branches so we don't always process everything. In some contexts we may need to limit accessibility of branches. However, bBot has a global root path, for adding all branches that should be accessible without specific context.


Matching Pattern

// Respond when someone says hello
bot.global.text(/hello/i, (b) => b.respond('Hello!'))

Matching Conditions

// Respond when someone says hello
bot.global.text({ contains: 'hello' }, (b) => b.respond('Hello!'))

Custom Matching

// Respond only on Wednesdays (with branch ID)
bot.global.custom((message) => {
  if (new Date().getDay() !== 3) return false
  else return /hello/i.test(message.toString())
}, (b) => b.respond('Hello!'), {
  id: 'wednesday-hello'

Force Matching

// React when someone says hi or hello
  contains: [ 'hi', 'hello' ]
}, (b) => b.respondVia('react', ':wave:'), {
  id: 'hello-react'

// Add another emoji to reaction when text contains "baby"
  contains: 'baby'
}, (b) => b.respondVia('react', ':baby:'), {
  id: 'baby-react', force: true

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