Function start

examples/11-using-facts-in-events.js:16–133

()

const { Engine, Fact } = require('json-rules-engine')

async function start () {
  /**
   * Setup a new engine
   */
  const engine = new Engine([], { replaceFactsInEventParams: true })

  // in-memory "database"
  let currentHighScore = null
  const currentHighScoreFact = new Fact('currentHighScore', () => currentHighScore)

  /**
   * Rule for when you've gotten the high score
   * event will include your score and initials.
   */
  const highScoreRule = {
    conditions: {
      any: [
        {
          fact: 'currentHighScore',
          operator: 'equal',
          value: null
        },
        {
          fact: 'score',
          operator: 'greaterThan',
          value: {
            fact: 'currentHighScore',
            path: '$.score'
          }
        }
      ]
    },
    event: {
      type: 'highscore',
      params: {
        initials: { fact: 'initials' },
        score: { fact: 'score' }
      }
    }
  }

  /**
   * Rule for when the game is over and you don't have the high score
   * event will include the previous high score
   */
  const gameOverRule = {
    conditions: {
      all: [
        {
          fact: 'score',
          operator: 'lessThanInclusive',
          value: {
            fact: 'currentHighScore',
            path: '$.score'
          }
        }
      ]
    },