perf: Add static Engine.evaluate() and shared operator registry for bulk evaluation

Author: mridulbarman027

src/engine-default-operator-decorators.js

@@ -2,13 +2,13 @@
 
 import OperatorDecorator from './operator-decorator'
 
-const OperatorDecorators = []
-
-OperatorDecorators.push(new OperatorDecorator('someFact', (factValue, jsonValue, next) => factValue.some(fv => next(fv, jsonValue)), Array.isArray))
-OperatorDecorators.push(new OperatorDecorator('someValue', (factValue, jsonValue, next) => jsonValue.some(jv => next(factValue, jv))))
-OperatorDecorators.push(new OperatorDecorator('everyFact', (factValue, jsonValue, next) => factValue.every(fv => next(fv, jsonValue)), Array.isArray))
-OperatorDecorators.push(new OperatorDecorator('everyValue', (factValue, jsonValue, next) => jsonValue.every(jv => next(factValue, jv))))
-OperatorDecorators.push(new OperatorDecorator('swap', (factValue, jsonValue, next) => next(jsonValue, factValue)))
-OperatorDecorators.push(new OperatorDecorator('not', (factValue, jsonValue, next) => !next(factValue, jsonValue)))
+const OperatorDecorators = Object.freeze([
+  new OperatorDecorator('someFact', (factValue, jsonValue, next) => factValue.some(fv => next(fv, jsonValue)), Array.isArray),
+  new OperatorDecorator('someValue', (factValue, jsonValue, next) => jsonValue.some(jv => next(factValue, jv))),
+  new OperatorDecorator('everyFact', (factValue, jsonValue, next) => factValue.every(fv => next(fv, jsonValue)), Array.isArray),
+  new OperatorDecorator('everyValue', (factValue, jsonValue, next) => jsonValue.every(jv => next(factValue, jv))),
+  new OperatorDecorator('swap', (factValue, jsonValue, next) => next(jsonValue, factValue)),
+  new OperatorDecorator('not', (factValue, jsonValue, next) => !next(factValue, jsonValue))
+])
 
 export default OperatorDecorators

src/engine-default-operators.js

@@ -2,21 +2,21 @@
 
 import Operator from './operator'
 
-const Operators = []
-Operators.push(new Operator('equal', (a, b) => a === b))
-Operators.push(new Operator('notEqual', (a, b) => a !== b))
-Operators.push(new Operator('in', (a, b) => b.indexOf(a) > -1))
-Operators.push(new Operator('notIn', (a, b) => b.indexOf(a) === -1))
-
-Operators.push(new Operator('contains', (a, b) => a.indexOf(b) > -1, Array.isArray))
-Operators.push(new Operator('doesNotContain', (a, b) => a.indexOf(b) === -1, Array.isArray))
-
 function numberValidator (factValue) {
   return Number.parseFloat(factValue).toString() !== 'NaN'
 }
-Operators.push(new Operator('lessThan', (a, b) => a < b, numberValidator))
-Operators.push(new Operator('lessThanInclusive', (a, b) => a <= b, numberValidator))
-Operators.push(new Operator('greaterThan', (a, b) => a > b, numberValidator))
-Operators.push(new Operator('greaterThanInclusive', (a, b) => a >= b, numberValidator))
+
+const Operators = Object.freeze([
+  new Operator('equal', (a, b) => a === b),
+  new Operator('notEqual', (a, b) => a !== b),
+  new Operator('in', (a, b) => b.indexOf(a) > -1),
+  new Operator('notIn', (a, b) => b.indexOf(a) === -1),
+  new Operator('contains', (a, b) => a.indexOf(b) > -1, Array.isArray),
+  new Operator('doesNotContain', (a, b) => a.indexOf(b) === -1, Array.isArray),
+  new Operator('lessThan', (a, b) => a < b, numberValidator),
+  new Operator('lessThanInclusive', (a, b) => a <= b, numberValidator),
+  new Operator('greaterThan', (a, b) => a > b, numberValidator),
+  new Operator('greaterThanInclusive', (a, b) => a >= b, numberValidator)
+])
 
 export default Operators

src/engine.js

@@ -26,13 +26,11 @@ class Engine extends EventEmitter {
     this.allowUndefinedConditions = options.allowUndefinedConditions || false
     this.replaceFactsInEventParams = options.replaceFactsInEventParams || false
     this.pathResolver = options.pathResolver
-    this.operators = new OperatorMap()
+    this.operators = new OperatorMap({ parent: OperatorMap.shared() })
     this.facts = new Map()
     this.conditions = new Map()
     this.status = READY
     rules.map(r => this.addRule(r))
-    defaultOperators.map(o => this.addOperator(o))
-    defaultDecorators.map(d => this.addOperatorDecorator(d))
   }
 
   /**
@@ -319,6 +317,112 @@ class Engine extends EventEmitter {
       }).catch(reject)
     })
   }
+
+  /**
+   * Lightweight static evaluation of conditions against facts using the shared operator registry.
+   * Avoids EventEmitter, Rule, and full Almanac overhead for high-throughput bulk evaluation.
+   *
+   * @param {Object} conditions - condition tree with all/any/not structure
+   * @param {Object} facts - plain object of fact key-value pairs
+   * @param {Object} [options] - evaluation options
+   * @param {boolean} [options.allowUndefinedFacts=false] - allow undefined fact references
+   * @param {Function} [options.pathResolver] - custom path resolver for nested properties
+   * @param {OperatorMap} [options.operatorMap] - custom operator map (defaults to shared)
+   * @returns {Promise<{results: Array, failureResults: Array, events: Array, failureEvents: Array}>}
+   */
+  static evaluate (conditions, facts, options = {}) {
+    const operatorMap = options.operatorMap || OperatorMap.shared()
+
+    const almanac = new Almanac({
+      allowUndefinedFacts: options.allowUndefinedFacts || false,
+      pathResolver: options.pathResolver
+    })
+
+    for (const factId in facts) {
+      almanac.addFact(new Fact(factId, facts[factId]))
+    }
+
+    const rootCondition = new Condition(conditions)
+
+    const evaluateCondition = (condition) => {
+      if (condition.isBooleanOperator()) {
+        const subConditions = condition[condition.operator]
+        let comparisonPromise
+        if (condition.operator === 'all') {
+          comparisonPromise = all(subConditions)
+        } else if (condition.operator === 'any') {
+          comparisonPromise = any(subConditions)
+        } else {
+          comparisonPromise = notOp(subConditions)
+        }
+        return comparisonPromise.then((comparisonValue) => {
+          condition.result = comparisonValue === true
+          return condition.result
+        })
+      } else {
+        return condition
+          .evaluate(almanac, operatorMap)
+          .then((evaluationResult) => {
+            condition.factResult = evaluationResult.leftHandSideValue
+            condition.valueResult = evaluationResult.rightHandSideValue
+            condition.result = evaluationResult.result
+            return evaluationResult.result
+          })
+      }
+    }
+
+    const evaluateConditions = (conds, method) => {
+      if (!Array.isArray(conds)) conds = [conds]
+      return Promise.all(
+        conds.map((c) => evaluateCondition(c))
+      ).then((results) => {
+        return method.call(results, (r) => r === true)
+      })
+    }
+
+    const prioritizeAndRun = (conds, operator) => {
+      if (conds.length === 0) return Promise.resolve(operator === 'all')
+      if (conds.length === 1) return evaluateCondition(conds[0])
+      // No priority sorting in static evaluate — evaluate all at once
+      return operator === 'any'
+        ? evaluateConditions(conds, Array.prototype.some)
+        : evaluateConditions(conds, Array.prototype.every)
+    }
+
+    const any = (conds) => prioritizeAndRun(conds, 'any')
+    const all = (conds) => prioritizeAndRun(conds, 'all')
+    const notOp = (cond) => prioritizeAndRun([cond], 'not').then((r) => !r)
+
+    let rootPromise
+    if (rootCondition.any) {
+      rootPromise = any(rootCondition.any)
+    } else if (rootCondition.all) {
+      rootPromise = all(rootCondition.all)
+    } else if (rootCondition.not) {
+      rootPromise = notOp(rootCondition.not)
+    } else {
+      rootPromise = evaluateCondition(rootCondition)
+    }
+
+    return rootPromise.then((result) => {
+      const event = { type: 'evaluate' }
+      if (result) {
+        return {
+          results: [{ conditions: rootCondition, event, result: true }],
+          failureResults: [],
+          events: [event],
+          failureEvents: []
+        }
+      } else {
+        return {
+          results: [],
+          failureResults: [{ conditions: rootCondition, event, result: false }],
+          events: [],
+          failureEvents: [event]
+        }
+      }
+    })
+  }
 }
 
 export default Engine

src/operator-map.js

@@ -2,12 +2,31 @@
 
 import Operator from './operator'
 import OperatorDecorator from './operator-decorator'
+import defaultOperators from './engine-default-operators'
+import defaultDecorators from './engine-default-operator-decorators'
 import debug from './debug'
 
+let sharedInstance = null
+
 export default class OperatorMap {
-  constructor () {
+  constructor (options = {}) {
     this.operators = new Map()
     this.decorators = new Map()
+    this.parent = options.parent || null
+  }
+
+  /**
+   * Returns a shared OperatorMap pre-populated with default operators and decorators.
+   * This singleton is reused across Engine instances to avoid redundant allocations.
+   * @returns {OperatorMap}
+   */
+  static shared () {
+    if (!sharedInstance) {
+      sharedInstance = new OperatorMap()
+      defaultOperators.forEach(o => sharedInstance.addOperator(o))
+      defaultDecorators.forEach(d => sharedInstance.addOperatorDecorator(d))
+    }
+    return sharedInstance
   }
 
   /**
@@ -95,20 +114,31 @@ export default class OperatorMap {
 
   /**
    * Get the Operator, or null applies decorators as needed
+   * Checks local operators first, then falls back to parent if set.
    * @param {string} name - the name of the operator including any decorators
    * @returns an operator or null
    */
   get (name) {
+    // Fast path: check local cache first
+    if (this.operators.has(name)) {
+      return this.operators.get(name)
+    }
+
+    // Check parent for cached decorated operators
+    if (this.parent && this.parent.operators.has(name)) {
+      return this.parent.operators.get(name)
+    }
+
     const decorators = []
     let opName = name
     // while we don't already have this operator
-    while (!this.operators.has(opName)) {
+    while (!this._hasOperator(opName)) {
       // try splitting on the decorator symbol (:)
       const firstDecoratorIndex = opName.indexOf(':')
       if (firstDecoratorIndex > 0) {
         // if there is a decorator, and it's a valid decorator
         const decoratorName = opName.slice(0, firstDecoratorIndex)
-        const decorator = this.decorators.get(decoratorName)
+        const decorator = this._getDecorator(decoratorName)
         if (!decorator) {
           debug('operatorMap::get invalid decorator', { name: decoratorName })
           return null
@@ -123,7 +153,7 @@ export default class OperatorMap {
       }
     }
 
-    let op = this.operators.get(opName)
+    let op = this._getOperator(opName)
     // apply all the decorators
     for (let i = 0; i < decorators.length; i++) {
       op = decorators[i].decorate(op)
@@ -134,4 +164,25 @@ export default class OperatorMap {
     // return the operation
     return op
   }
+
+  /**
+   * Check if operator exists locally or in parent
+   */
+  _hasOperator (name) {
+    return this.operators.has(name) || (this.parent && this.parent.operators.has(name))
+  }
+
+  /**
+   * Get operator from local map or parent
+   */
+  _getOperator (name) {
+    return this.operators.get(name) || (this.parent && this.parent.operators.get(name))
+  }
+
+  /**
+   * Get decorator from local map or parent
+   */
+  _getDecorator (name) {
+    return this.decorators.get(name) || (this.parent && this.parent.decorators.get(name))
+  }
 }