feat(change_detector): wrap exceptions into ChangeDetectionError

ChangeDetectionError references the original error and the location where the error happened

modules/change_detection/src/change_detector.js

@@ -19,6 +19,22 @@ class ExpressionChangedAfterItHasBeenChecked extends Error {
   }
 }
 
+export class ChangeDetectionError extends Error {
+  message:string;
+  originalException:any;
+  location:string;
+
+  constructor(record:Record, originalException:any) {
+    this.originalException = originalException;
+    this.location = record.protoRecord.expressionAsString;
+    this.message = `${this.originalException} in [${this.location}]`;
+  }
+
+  toString():string {
+    return this.message;
+  }
+}
+
 export class ChangeDetector {
   _rootRecordRange:RecordRange;
   _enforceNoNewChanges:boolean;
@@ -42,28 +58,32 @@ export class ChangeDetector {
     var record = this._rootRecordRange.findFirstEnabledRecord();
     var currentRange, currentGroup;
 
-    while (isPresent(record)) {
-      if (record.check()) {
-        count++;
-        if (record.terminatesExpression()) {
-          if (throwOnChange) throw new ExpressionChangedAfterItHasBeenChecked(record);
-          currentRange = record.recordRange;
-          currentGroup = record.groupMemento();
-          updatedRecords = this._addRecord(updatedRecords, record);
+    try {
+      while (isPresent(record)) {
+        if (record.check()) {
+          count++;
+          if (record.terminatesExpression()) {
+            if (throwOnChange) throw new ExpressionChangedAfterItHasBeenChecked(record);
+            currentRange = record.recordRange;
+            currentGroup = record.groupMemento();
+            updatedRecords = this._addRecord(updatedRecords, record);
+          }
         }
-      }
 
-      if (isPresent(updatedRecords)) {
-        var nextEnabled = record.nextEnabled;
-        if (isBlank(nextEnabled) ||                       // we have reached the last enabled record
-            currentRange != nextEnabled.recordRange ||    // the next record is in a different range
-            currentGroup != nextEnabled.groupMemento()) { // the next record is in a different group
-          currentRange.dispatcher.onRecordChange(currentGroup, updatedRecords);
-          updatedRecords = null;
+        if (isPresent(updatedRecords)) {
+          var nextEnabled = record.nextEnabled;
+          if (isBlank(nextEnabled) ||                       // we have reached the last enabled record
+              currentRange != nextEnabled.recordRange ||    // the next record is in a different range
+              currentGroup != nextEnabled.groupMemento()) { // the next record is in a different group
+            currentRange.dispatcher.onRecordChange(currentGroup, updatedRecords);
+            updatedRecords = null;
+          }
         }
-      }
 
-      record = record.findNextEnabled();
+        record = record.findNextEnabled();
+      }
+    } catch(e) {
+      throw new ChangeDetectionError(record, e);
     }
 
     return count;

modules/change_detection/test/change_detector_spec.js

@@ -1,6 +1,6 @@
 import {ddescribe, describe, it, iit, xit, expect, beforeEach} from 'test_lib/test_lib';
 
-import {isPresent, isBlank, isJsObject} from 'facade/lang';
+import {isPresent, isBlank, isJsObject, BaseException} from 'facade/lang';
 import {List, ListWrapper, MapWrapper} from 'facade/collection';
 import {ContextWithVariableBindings} from 'change_detection/parser/context_with_variable_bindings';
 import {Parser} from 'change_detection/parser/parser';
@@ -12,15 +12,16 @@ import {
   ProtoRecordRange,
   RecordRange,
   ChangeDispatcher,
-  ProtoRecord
+  ProtoRecord,
+  ChangeDetectionError
 } from 'change_detection/change_detector';
 
 import {Record} from 'change_detection/record';
 
 export function main() {
-  function ast(exp:string) {
+  function ast(exp:string, location:string = 'location') {
     var parser = new Parser(new Lexer());
-    return parser.parseBinding(exp, 'location');
+    return parser.parseBinding(exp, location);
   }
 
   function createChangeDetector(memo:string, exp:string, context = null, formatters = null,
@@ -271,7 +272,7 @@ export function main() {
           var context = new TestData("not collection / null");
           var c = createChangeDetector('a', 'a', context, null, true);
           expect(() => c["changeDetector"].detectChanges())
-            .toThrowError("Collection records must be array like, map like or null");
+            .toThrowError(new RegExp("Collection records must be array like, map like or null"));
         });
 
         describe("list", () => {
@@ -454,6 +455,20 @@ export function main() {
           }).toThrowError(new RegExp("Expression 'a in location' has changed after it was checked"));
         });
       });
+
+      describe("error handling", () => {
+        it("should wrap exceptions into ChangeDetectionError", () => {
+          try {
+            var rr = createRange(new TestDispatcher(), ast("invalidProp", "someComponent"), 1);
+            detectChangesInRange(rr);
+
+            throw new BaseException("fail");
+          } catch (e) {
+            expect(e).toBeAnInstanceOf(ChangeDetectionError);
+            expect(e.location).toEqual("invalidProp in someComponent");
+          }
+        });
+      });
     });
   });
 }