From b99ef2b80a5490a3fc79c2555f024c1d79f8f519 Mon Sep 17 00:00:00 2001
From: JoostK <joost.koehoorn@gmail.com>
Date: Sun, 13 May 2018 21:01:37 +0200
Subject: [PATCH] refactor(ivy): simplify bind instruction to reuse
 bindingUpdated logic (#23881)

Added runtime and compiler testcases for interpolated bindings, which verify
that NO_CHANGE is properly handled in `bind`.

PR Close #23881
---
 packages/core/src/render3/instructions.ts     | 19 ++--------
 .../core/test/render3/instructions_spec.ts    | 37 +++++++++++++++++++
 packages/core/test/render3/render_util.ts     |  6 +--
 3 files changed, 43 insertions(+), 19 deletions(-)

diff --git a/packages/core/src/render3/instructions.ts b/packages/core/src/render3/instructions.ts
index c577aa5200..523c605a68 100644
--- a/packages/core/src/render3/instructions.ts
+++ b/packages/core/src/render3/instructions.ts
@@ -1266,7 +1266,7 @@ export function text(index: number, value?: any): void {
 
 /**
  * Create text node with binding
- * Bindings should be handled externally with the proper bind(1-8) method
+ * Bindings should be handled externally with the proper interpolation(1-8) method
  *
  * @param index Index of the node in the data array.
  * @param value Stringified value to write.
@@ -2151,21 +2151,8 @@ function initBindings() {
  *
  * @param value Value to diff
  */
-export function bind<T>(value: T | NO_CHANGE): T|NO_CHANGE {
-  if (currentView.bindingStartIndex < 0) {
-    initBindings();
-    return data[currentView.bindingIndex++] = value;
-  }
-
-  const changed: boolean =
-      value !== NO_CHANGE && isDifferent(data[currentView.bindingIndex], value);
-  if (changed) {
-    throwErrorIfNoChangesMode(
-        creationMode, checkNoChangesMode, data[currentView.bindingIndex], value);
-    data[currentView.bindingIndex] = value;
-  }
-  currentView.bindingIndex++;
-  return changed ? value : NO_CHANGE;
+export function bind<T>(value: T): T|NO_CHANGE {
+  return bindingUpdated(value) ? value : NO_CHANGE;
 }
 
 /**
diff --git a/packages/core/test/render3/instructions_spec.ts b/packages/core/test/render3/instructions_spec.ts
index 43a0de4031..7a59ec8834 100644
--- a/packages/core/test/render3/instructions_spec.ts
+++ b/packages/core/test/render3/instructions_spec.ts
@@ -35,6 +35,43 @@ describe('instructions', () => {
     elementEnd();
   }
 
+  describe('bind', () => {
+    it('should update bindings when value changes', () => {
+      const t = new TemplateFixture(createAnchor);
+
+      t.update(() => elementProperty(0, 'title', bind('Hello')));
+      expect(t.html).toEqual('<a title="Hello"></a>');
+
+      t.update(() => elementProperty(0, 'title', bind('World')));
+      expect(t.html).toEqual('<a title="World"></a>');
+      expect(ngDevMode).toHaveProperties({
+        firstTemplatePass: 1,
+        tNode: 2,  // 1 for hostElement + 1 for the template under test
+        tView: 1,
+        rendererCreateElement: 1,
+        rendererSetProperty: 2
+      });
+    });
+
+    it('should not update bindings when value does not change', () => {
+      const idempotentUpdate = () => elementProperty(0, 'title', bind('Hello'));
+      const t = new TemplateFixture(createAnchor, idempotentUpdate);
+
+      t.update();
+      expect(t.html).toEqual('<a title="Hello"></a>');
+
+      t.update();
+      expect(t.html).toEqual('<a title="Hello"></a>');
+      expect(ngDevMode).toHaveProperties({
+        firstTemplatePass: 1,
+        tNode: 2,  // 1 for hostElement + 1 for the template under test
+        tView: 1,
+        rendererCreateElement: 1,
+        rendererSetProperty: 1
+      });
+    });
+  });
+
   describe('elementAttribute', () => {
     it('should use sanitizer function', () => {
       const t = new TemplateFixture(createDiv);
diff --git a/packages/core/test/render3/render_util.ts b/packages/core/test/render3/render_util.ts
index 7bb954e2cd..2486905eae 100644
--- a/packages/core/test/render3/render_util.ts
+++ b/packages/core/test/render3/render_util.ts
@@ -58,9 +58,9 @@ export class TemplateFixture extends BaseFixture {
   /**
    *
    * @param createBlock Instructions which go into the creation block:
-   *          `if (creationMode) { __here__ }`.
-   * @param updateBlock Optional instructions which go after the creation block:
-   *          `if (creationMode) { ... } __here__`.
+   *          `if (rf & RenderFlags.Create) { __here__ }`.
+   * @param updateBlock Optional instructions which go into the update block:
+   *          `if (rf & RenderFlags.Update) { __here__ }`.
    */
   constructor(
       private createBlock: () => void, private updateBlock: () => void = noop,