@logosnetwork/logos-webwallet-sdk/src/Utils/mqttPattern.ts

Create Logos wallets with or without a full Logos node

const SEPARATOR = '/'
const SINGLE = '+'
const ALL = '#'

const matches = (pattern: string, topic: string): boolean => {
  const patternSegments = pattern.split(SEPARATOR)
  const topicSegments = topic.split(SEPARATOR)

  const patternLength = patternSegments.length
  const topicLength = topicSegments.length
  const lastIndex = patternLength - 1

  for (let i = 0; i < patternLength; i++) {
    const currentPattern = patternSegments[i]
    const patternChar = currentPattern[0]
    const currentTopic = topicSegments[i]

    if (!currentTopic && !currentPattern) { continue }

    if (!currentTopic && currentPattern !== ALL) return false

    // Only allow # at end
    if (patternChar === ALL) { return i === lastIndex }
    if (patternChar !== SINGLE && currentPattern !== currentTopic) { return false }
  }

  return patternLength === topicLength
}
interface Pattern {
  [currentPattern: string]: string|string[];
}
const extract = (pattern: string, topic: string): Pattern => {
  const params = {}
  const patternSegments = pattern.split(SEPARATOR)
  const topicSegments = topic.split(SEPARATOR)

  const patternLength = patternSegments.length

  for (let i = 0; i < patternLength; i++) {
    const currentPattern = patternSegments[i]
    const patternChar = currentPattern[0]

    if (currentPattern.length === 1) { continue }

    if (patternChar === ALL) {
      params[currentPattern.slice(1)] = topicSegments.slice(i)
      break
    } else if (patternChar === SINGLE) {
      params[currentPattern.slice(1)] = topicSegments[i]
    }
  }

  return params
}

export default (pattern: string, topic: string): Pattern => {
  return matches(pattern, topic) ? extract(pattern, topic) : null
}