facts.md

Facts

Facts are methods or constants registered with the engine prior to runtime and referenced within rule conditions. Each fact method should be a pure function that may return a either computed value, or promise that resolves to a computed value. As rule conditions are evaluated during runtime, they retrieve fact values dynamically and use the condition operator to compare the fact result with the condition value.

• Methods
  • constructor(String id, Constant|Function(Object params, Almanac almanac), [Object options]) -> instance

Methods

constructor(String id, Constant|Function(Object params, Almanac almanac), [Object options]) -> instance

// constant value facts
let fact = new Fact('apiKey', '4feca34f9d67e99b8af2')

// dynamic facts
let fact = new Fact('account-type', (params, almanac) => {
  // ...
})

// facts with options:
engine.addFact('account-type', (params, almanac) => {
  // ...
}, { cache: false, priority: 500 })

options

• { cache: Boolean } - Sets whether the engine should cache the result of this fact. Cache key is based on the factId and 'params' passed to it. Default: true
• { priority: Integer } - Sets when the fact should run in relation to other facts and conditions. The higher the priority value, the sooner the fact will run. Default: 1