feat(empower-core): trying to extract core functionalities out

Author: twada

index.js

@@ -44,10 +44,21 @@ function empower (assert, options) {
     return enhancedAssert;
 }
 
+function onError (ev) {
+    var e = ev.error;
+    var message = ev.originalMessage;
+    var context = ev.powerAssertContext;
+    if (e.name !== 'AssertionError') {
+        throw e;
+    }
+    e.powerAssertContext = context;
+    throw e;
+};
+
 function empowerAssertObject (assertObject, options) {
     var config = extend(defaultOptions(), options);
     var target = config.destructive ? assertObject : create(assertObject);
-    var decorator = new Decorator(target, config);
+    var decorator = new Decorator(target, onError, config);
     return extend(target, decorator.enhancement());
 }
 
@@ -56,7 +67,7 @@ function empowerAssertFunction (assertFunction, options) {
     if (config.destructive) {
         throw new Error('cannot use destructive:true to function.');
     }
-    var decorator = new Decorator(assertFunction, config);
+    var decorator = new Decorator(assertFunction, onError, config);
     var enhancement = decorator.enhancement();
     var powerAssert;
     if (typeof enhancement === 'function') {

lib/decorator.js

@@ -8,9 +8,10 @@ var filter = require('array-filter');
 var decorate = require('./decorate');
 
 
-function Decorator (receiver, config) {
+function Decorator (receiver, onError, config) {
     this.receiver = receiver;
     this.config = config;
+    this.onError = onError;
     this.signatures = map(config.patterns, signature.parse);
     this.eagerEvaluation = !(config.modifyMessageOnRethrow || config.saveContextOnRethrow);
 }
@@ -56,31 +57,10 @@ Decorator.prototype.concreteAssert = function (invocation, context) {
     try {
         return func.apply(thisObj, args.concat(message));
     } catch (e) {
-        throw this.errorToRethrow(e, message, context);
+        this.onError({error: e, originalMessage: message, powerAssertContext: context});
     }
 };
 
-Decorator.prototype.errorToRethrow = function (e, originalMessage, context) {
-    if (e.name !== 'AssertionError') {
-        return e;
-    }
-    if (typeof this.receiver.AssertionError !== 'function') {
-        return e;
-    }
-    var f = new this.receiver.AssertionError({
-        actual: e.actual,
-        expected: e.expected,
-        operator: e.operator,
-        message: e.message,
-        stackStartFunction: Decorator.prototype.concreteAssert
-    });
-    if (this.config.saveContextOnRethrow) {
-        f.powerAssertContext = context;
-    }
-    return f;
-};
-
-
 function numberOfArgumentsToCapture (matcher) {
     var len = matcher.args.length;
     var lastArg;