Add a permissive mode to resolve Issue #6.

asyncLogic.js

@@ -19,13 +19,14 @@ class AsyncLogicEngine {
   /**
    *
    * @param {Object} methods An object that stores key-value pairs between the names of the commands & the functions they execute.
-   * @param {{ yieldSupported?: Boolean, disableInline?: Boolean }} options
+   * @param {{ yieldSupported?: Boolean, disableInline?: Boolean, permissive?: boolean }} options
    */
   constructor (
     methods = defaultMethods,
-    options = { yieldSupported: false, disableInline: false }
+    options = { yieldSupported: false, disableInline: false, permissive: false }
   ) {
     this.methods = { ...methods }
+    /** @type {{yieldSupported?: Boolean, disableInline?: Boolean, permissive?: boolean}} */
     this.options = { ...options }
     this.disableInline = options.disableInline
     this.async = true
@@ -73,6 +74,8 @@ class AsyncLogicEngine {
         return Array.isArray(result) ? Promise.all(result) : result
       }
     }
+    if (this.options.permissive) return { [func]: data }
+    throw new Error(`Method '${func}' was not found in the Logic Engine.`)
   }
 
   /**

compiler.js

@@ -271,7 +271,11 @@ function buildString (method, buildState = {}) {
     buildState.useContext || (engine.methods[func] || {}).useContext
 
   if (method && typeof method === 'object') {
-    if (!engine.methods[func]) throw new Error(`Method '${func}' was not found in the Logic Engine.`)
+    if (!engine.methods[func]) {
+      // If we are in permissive mode, we will just return the object.
+      if (engine.options.permissive) return pushValue(method)
+      throw new Error(`Method '${func}' was not found in the Logic Engine.`)
+    }
     functions[func] = functions[func] || 2
 
     if (

defaultMethods.js

@@ -16,6 +16,9 @@ function isDeterministic (method, engine, buildState) {
   if (method && typeof method === 'object') {
     const func = Object.keys(method)[0]
     const lower = method[func]
+
+    if (!engine.methods[func] && engine.options.permissive) return true
+
     if (engine.methods[func].traverse === false) {
       return typeof engine.methods[func].deterministic === 'function'
         ? engine.methods[func].deterministic(lower, buildState)

general.test.js

@@ -0,0 +1,89 @@
+
+import assert from 'assert'
+import { LogicEngine, AsyncLogicEngine } from './index.js'
+
+const normalEngines = [
+  new LogicEngine(),
+  new AsyncLogicEngine(),
+  new LogicEngine(undefined, { yieldSupported: true }),
+  new AsyncLogicEngine(undefined, { yieldSupported: true })
+]
+
+const permissiveEngines = [
+  new LogicEngine(undefined, { permissive: true }),
+  new AsyncLogicEngine(undefined, { permissive: true }),
+  new LogicEngine(undefined, { yieldSupported: true, permissive: true }),
+  new AsyncLogicEngine(undefined, { yieldSupported: true, permissive: true })
+]
+
+async function testEngineAsync (engine, rule, data, expected) {
+  // run
+  if (expected === Error) {
+    try {
+      await engine.run(rule, data)
+      throw new Error('Should have failed')
+    } catch (e) {}
+  } else {
+    const result = await engine.run(rule, data)
+    assert.deepStrictEqual(result, expected)
+  }
+
+  // build
+  if (expected === Error) {
+    try {
+      const built = await engine.build(rule)
+      await built(data)
+      throw new Error('Should have failed')
+    } catch (e) {}
+  } else {
+    const built = await engine.build(rule)
+    const builtResult = await built(data)
+    assert.deepStrictEqual(builtResult, expected)
+  }
+}
+
+function testEngine (engine, rule, data, expected) {
+  if (engine instanceof AsyncLogicEngine) {
+    return testEngineAsync(engine, rule, data, expected)
+  }
+
+  // run
+  if (expected === Error) {
+    try {
+      engine.run(rule, data)
+      throw new Error('Should have failed')
+    } catch (e) {}
+  } else {
+    const result = engine.run(rule, data)
+    assert.deepStrictEqual(result, expected)
+  }
+
+  // build
+  if (expected === Error) {
+    try {
+      const built = engine.build(rule)
+      built(data)
+      throw new Error('Should have failed')
+    } catch (e) {}
+  } else {
+    const built = engine.build(rule)
+    const builtResult = built(data)
+    assert.deepStrictEqual(builtResult, expected)
+  }
+}
+
+describe('Various Test Cases', () => {
+  it('Should fail when an unrecognized method is used.', async () => {
+    for (const engine of normalEngines) await testEngine(engine, { unknown: true }, {}, Error)
+  })
+
+  it('Should return the object when an unrecognized method is used.', async () => {
+    for (const engine of permissiveEngines) {
+      await testEngine(engine, { unknown: true }, {}, { unknown: true })
+
+      await testEngine(engine, {
+        if: [true, { unknown: true }, 5]
+      }, {}, { unknown: true })
+    }
+  })
+})

logic.js

@@ -16,14 +16,15 @@ class LogicEngine {
   /**
    *
    * @param {Object} methods An object that stores key-value pairs between the names of the commands & the functions they execute.
-   * @param {{ yieldSupported?: Boolean, disableInline?: Boolean }} options
+   * @param {{ yieldSupported?: Boolean, disableInline?: Boolean, permissive?: boolean }} options
    */
   constructor (
     methods = defaultMethods,
-    options = { yieldSupported: false, disableInline: false }
+    options = { yieldSupported: false, disableInline: false, permissive: false }
   ) {
     this.disableInline = options.disableInline
     this.methods = { ...methods }
+    /** @type {{yieldSupported?: Boolean, disableInline?: Boolean, permissive?: boolean}} */
     this.options = { ...options }
   }
 
@@ -44,17 +45,16 @@ class LogicEngine {
       }
       if (typeof this.methods[func] === 'object') {
         const { method, traverse } = this.methods[func]
-        const shouldTraverse =
-          typeof traverse === 'undefined' ? true : traverse
+        const shouldTraverse = typeof traverse === 'undefined' ? true : traverse
         const parsedData = shouldTraverse
           ? this.run(data, context, { above })
           : data
-        if (this.options.yieldSupported && checkYield(parsedData)) {
-          return parsedData
-        }
+        if (this.options.yieldSupported && checkYield(parsedData)) return parsedData
         return method(parsedData, context, above, this)
       }
     }
+    if (this.options.permissive) return { [func]: data }
+    throw new Error(`Method '${func}' was not found in the Logic Engine.`)
   }
 
   /**

package.json

@@ -1,6 +1,6 @@
 {
   "name": "json-logic-engine",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "description": "Construct complex rules with JSON & process them.",
   "main": "./dist/cjs/index.js",
   "module": "./dist/esm/index.js",