From 1320175646e7c6341313a34974149a7203d73d1c Mon Sep 17 00:00:00 2001
From: Stephen Adams <sra@google.com>
Date: Wed, 7 Jan 2015 11:47:25 -0800
Subject: [PATCH] perf(change detection): minimized amount of code in
 protective try-catch

---
 .../change_detection/src/change_detector.js   | 60 +++++++------------
 modules/change_detection/src/record.js        | 30 +++++++++-
 2 files changed, 48 insertions(+), 42 deletions(-)

diff --git a/modules/change_detection/src/change_detector.js b/modules/change_detection/src/change_detector.js
index 6481c58971..2522245490 100644
--- a/modules/change_detection/src/change_detector.js
+++ b/modules/change_detection/src/change_detector.js
@@ -19,22 +19,6 @@ 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;
@@ -58,32 +42,28 @@ export class ChangeDetector {
     var record = this._rootRecordRange.findFirstEnabledRecord();
     var currentRange, currentGroup;
 
-    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);
-          }
+    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;
-          }
-        }
-
-        record = record.findNextEnabled();
       }
-    } catch(e) {
-      throw new ChangeDetectionError(record, e);
+
+      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();
     }
 
     return count;
diff --git a/modules/change_detection/src/record.js b/modules/change_detection/src/record.js
index 0840dfbc0c..c0352a7cb3 100644
--- a/modules/change_detection/src/record.js
+++ b/modules/change_detection/src/record.js
@@ -274,12 +274,22 @@ export class Record {
   }
 
   _calculateNewValue() {
+    try {
+      return this.__calculateNewValue();
+    } catch (e) {
+      throw new ChangeDetectionError(this, e);
+    }
+  }
+
+  __calculateNewValue() {
     switch (this.getType()) {
       case RECORD_TYPE_PROPERTY:
-        return this.funcOrValue(this.context);
+        var propertyGetter:Function = this.funcOrValue;
+        return propertyGetter(this.context);
 
       case RECORD_TYPE_INVOKE_METHOD:
-        return this.funcOrValue(this.context, this.args);
+        var methodInvoker:Function = this.funcOrValue;
+        return methodInvoker(this.context, this.args);
 
       case RECORD_TYPE_INVOKE_CLOSURE:
         return FunctionWrapper.apply(this.context, this.args);
@@ -477,3 +487,19 @@ function isSame(a, b) {
   if ((a !== a) && (b !== b)) return true;
   return false;
 }
+
+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;
+  }
+}