Merge pull request #6 from Tiliqua/instanceof-fix

Fixed instanceof assertion when expected argument is not a valid class

Author: norberttech

bin/JSAssert/Assert.js

@@ -26,10 +26,10 @@ var Assert = function () {
 
         /**
          * @param {object} objectValue
-         * @param {function} instance
+         * @param {function} expectedInstance
          * @param {string} [message]
          */
-        value: function instanceOf(objectValue, instance) {
+        value: function instanceOf(objectValue, expectedInstance) {
             var message = arguments.length <= 2 || arguments[2] === undefined ? "" : arguments[2];
 
             this.string(message, "Custom error message passed to Assert.instanceOf needs to be a valid string.");
@@ -38,8 +38,10 @@ var Assert = function () {
                 throw _InvalidValueException2.default.expected("object", objectValue, message);
             }
 
-            if (!(objectValue instanceof instance)) {
-                throw _InvalidValueException2.default.expected(instance.name, objectValue, message.length ? message : "Expected instance of \"${expected}\" but got \"${received}\".");
+            this.isFunction(expectedInstance, "Expected argument needs to be a valid class instead of that got \"${received}\". Most likely there is typo in class name or file with class is missing export declaration.");
+
+            if (!(objectValue instanceof expectedInstance)) {
+                throw _InvalidValueException2.default.expected(expectedInstance.name, objectValue, message.length ? message : "Expected instance of \"${expected}\" but got \"${received}\".");
             }
         }
 

spec/Doubles/ObjectWithNoExportStub.js

@@ -0,0 +1,6 @@
+'use strict';
+
+class ObjectWithNoExportStub
+{
+    
+}

spec/JSAssert/AssertSpec.js

@@ -1,10 +1,17 @@
 import Assert from '../../src/JSAssert/Assert';
 
+import ObjectWithNoExportStub from './../Doubles/ObjectWithNoExportStub';
+
 describe("Assert", () => {
     it("compares instance of", () => {
         Assert.instanceOf(new String("string"), String);
     });
 
+    it("compares instance of when object has no export", () => {
+        expect(() => { Assert.instanceOf(new String("test"), ObjectWithNoExportStub); })
+            .toThrow(`Expected argument needs to be a valid class instead of that got "object[{}]". Most likely there is typo in class name or file with class is missing export declaration.`);
+    });
+
     it ("throws error when asserting instance of non object", () => {
         expect(() => {Assert.instanceOf(1, String)}).toThrow('Expected object but got "int[1]".');
         expect(() => {Assert.instanceOf(new Number(2), String)}).toThrow('Expected instance of "String" but got "Number:int[2]".');
@@ -209,11 +216,11 @@ describe("Assert", () => {
         expect(() => {Assert.notEmpty("")}).toThrow('Expected not empty value but got "string[""]".');
         expect(() => {Assert.notEmpty("", 'custom message')}).toThrow('custom message');
     });
-    
+
     it ("asserts json string", () => {
         Assert.jsonString('{"key":"value"}');
     });
-    
+
     it ("throws error when expected json string is not valid", () => {
         expect(() => {Assert.jsonString('{"key":value"}')}).toThrow('Expected json string but got "string["{"key":value"}"]".');
         expect(() => {Assert.jsonString('{"key":value"}', "custom message")}).toThrow('custom message');

src/JSAssert/Assert.js

@@ -6,20 +6,25 @@ export default class Assert
 {
     /**
      * @param {object} objectValue
-     * @param {function} instance
+     * @param {function} expectedInstance
      * @param {string} [message]
      */
-    static instanceOf(objectValue, instance, message = "")
+    static instanceOf(objectValue, expectedInstance, message = "")
     {
         this.string(message, "Custom error message passed to Assert.instanceOf needs to be a valid string.");
 
         if (typeof objectValue !== 'object') {
             throw InvalidValueException.expected("object", objectValue, message);
         }
 
-        if (!(objectValue instanceof instance)) {
+        this.isFunction(
+            expectedInstance,
+            "Expected argument needs to be a valid class instead of that got \"${received}\". Most likely there is typo in class name or file with class is missing export declaration."
+        );
+
+        if (!(objectValue instanceof expectedInstance)) {
             throw InvalidValueException.expected(
-                instance.name,
+                expectedInstance.name,
                 objectValue,
                 message.length ? message : "Expected instance of \"${expected}\" but got \"${received}\"."
             );
@@ -279,7 +284,7 @@ export default class Assert
             throw InvalidValueException.expected("even number", integerValue, message);
         }
     }
-    
+
     /**
      * @param {string} stringValue
      * @param {string} [message]