Method evaluate

src/condition.js:90–115

* Takes the fact result and compares it to the condition 'value', using the operator * LHS OPER RHS * * * @param {Almanac} almanac * @param {Map} operatorMap - map of available operators, keyed by operator na

(almanac, operatorMap)

   * @returns {Boolean} - evaluation result
   */
  evaluate (almanac, operatorMap) {
    if (!almanac) return Promise.reject(new Error('almanac required'))
    if (!operatorMap) return Promise.reject(new Error('operatorMap required'))
    if (this.isBooleanOperator()) { return Promise.reject(new Error('Cannot evaluate() a boolean condition')) }

    const op = operatorMap.get(this.operator)
    if (!op) { return Promise.reject(new Error(`Unknown operator: ${this.operator}`)) }

    return Promise.all([
      almanac.getValue(this.value),
      almanac.factValue(this.fact, this.params, this.path)
    ]).then(([rightHandSideValue, leftHandSideValue]) => {
      const result = op.evaluate(leftHandSideValue, rightHandSideValue)
      debug(
        `condition::evaluate <${JSON.stringify(leftHandSideValue)} ${
          this.operator
        } ${JSON.stringify(rightHandSideValue)}?> (${result})`
      )
      return {
        result,
        leftHandSideValue,
        rightHandSideValue,
        operator: this.operator
      }
    })
  }

  /**
   * Returns the boolean operator for the condition