refactor(core): Improve tree shakability of i18n code. (#39301)

`TNode.insertBeforeIndex` is only populated when i18n is present. This
change puts all code which reads `insertBeforeIndex` behind a
dynamically loaded functions which are set only when i18n code executes.

PR Close #39301

goldens/size-tracking/integration-payloads.json

@@ -12,7 +12,7 @@
     "master": {
       "uncompressed": {
         "runtime-es2015": 1485,
-        "main-es2015": 17092,
+        "main-es2015": 17049,
         "polyfills-es2015": 36657
       }
     }
@@ -49,7 +49,7 @@
     "master": {
       "uncompressed": {
         "runtime-es2015": 2289,
-        "main-es2015": 218527,
+        "main-es2015": 217879,
         "polyfills-es2015": 36723,
         "5-es2015": 781
       }

packages/core/src/render3/i18n/i18n_insert_before_index.ts

@@ -8,6 +8,8 @@
 
 import {assertEqual} from '../../util/assert';
 import {TNode, TNodeType} from '../interfaces/node';
+import {setI18nHandling} from '../node_manipulation';
+import {getInsertInFrontOfRNodeWithI18n, processI18nInsertBefore} from '../node_manipulation_i18n';
 
 /**
  * Add `tNode` to `previousTNodes` list and update relevant `TNode`s in `previousTNodes` list
@@ -81,6 +83,7 @@ function setInsertBeforeIndex(tNode: TNode, value: number): void {
     // Array is stored if we have to insert child nodes. See `TNode.insertBeforeIndex`
     index[0] = value;
   } else {
+    setI18nHandling(getInsertInFrontOfRNodeWithI18n, processI18nInsertBefore);
     tNode.insertBeforeIndex = value;
   }
 }

packages/core/src/render3/i18n/i18n_parse.ts

@@ -117,7 +117,7 @@ export function i18nStartFirstCreatePass(
       }
     } else {
       // Odd indexes are placeholders (elements and sub-templates)
-      // At this point value is something like: '/#1:2' (orginally coming from '�/#1:2�')
+      // At this point value is something like: '/#1:2' (originally coming from '�/#1:2�')
       const isClosing = value.charCodeAt(0) === CharCode.SLASH;
       const type = value.charCodeAt(isClosing ? 1 : 0);
       ngDevMode && assertOneOf(type, CharCode.STAR, CharCode.HASH, CharCode.EXCLAMATION);

packages/core/src/render3/i18n/i18n_util.ts

@@ -13,6 +13,8 @@ import {IcuCreateOpCode, TIcu} from '../interfaces/i18n';
 import {TIcuContainerNode, TNode, TNodeType} from '../interfaces/node';
 import {LView, TView} from '../interfaces/view';
 import {assertTNodeType} from '../node_assert';
+import {setI18nHandling} from '../node_manipulation';
+import {getInsertInFrontOfRNodeWithI18n, processI18nInsertBefore} from '../node_manipulation_i18n';
 import {addTNodeAndUpdateInsertBeforeIndex} from './i18n_insert_before_index';
 
 
@@ -83,6 +85,7 @@ export function setTNodeInsertBeforeIndex(tNode: TNode, index: number) {
   ngDevMode && assertTNode(tNode);
   let insertBeforeIndex = tNode.insertBeforeIndex;
   if (insertBeforeIndex === null) {
+    setI18nHandling(getInsertInFrontOfRNodeWithI18n, processI18nInsertBefore);
     insertBeforeIndex = tNode.insertBeforeIndex =
         [null!/* may be updated to number later */, index];
   } else {

packages/core/src/render3/instructions/shared.ts

@@ -12,7 +12,7 @@ import {CUSTOM_ELEMENTS_SCHEMA, NO_ERRORS_SCHEMA, SchemaMetadata} from '../../me
 import {ViewEncapsulation} from '../../metadata/view';
 import {validateAgainstEventAttributes, validateAgainstEventProperties} from '../../sanitization/sanitization';
 import {Sanitizer} from '../../sanitization/sanitizer';
-import {assertDefined, assertDomNode, assertEqual, assertGreaterThan, assertGreaterThanOrEqual, assertIndexInRange, assertNotEqual, assertNotSame, assertSame, assertString} from '../../util/assert';
+import {assertDefined, assertDomNode, assertEqual, assertGreaterThanOrEqual, assertIndexInRange, assertNotEqual, assertNotSame, assertSame, assertString} from '../../util/assert';
 import {createNamedArrayType} from '../../util/named_array_type';
 import {initNgDevMode} from '../../util/ng_dev_mode';
 import {normalizeDebugBindingName, normalizeDebugBindingValue} from '../../util/ng_reflect';

packages/core/src/render3/node_manipulation.ts

@@ -639,28 +639,64 @@ export function nativeNextSibling(renderer: Renderer3, node: RNode): RNode|null
  * Find a node in front of which `currentTNode` should be inserted.
  *
  * This method determines the `RNode` in front of which we should insert the `currentRNode`. This
- * takes `TNode.insertBeforeIndex` into account.
+ * takes `TNode.insertBeforeIndex` into account if i18n code has been invoked.
  *
  * @param parentTNode parent `TNode`
  * @param currentTNode current `TNode` (The node which we would like to insert into the DOM)
  * @param lView current `LView`
  */
 function getInsertInFrontOfRNode(parentTNode: TNode, currentTNode: TNode, lView: LView): RNode|
     null {
-  const tNodeInsertBeforeIndex = currentTNode.insertBeforeIndex;
-  const insertBeforeIndex =
-      Array.isArray(tNodeInsertBeforeIndex) ? tNodeInsertBeforeIndex[0] : tNodeInsertBeforeIndex;
-  if (insertBeforeIndex === null) {
-    if (parentTNode.type & (TNodeType.ElementContainer | TNodeType.Icu)) {
-      return getNativeByTNode(parentTNode, lView);
-    }
-  } else {
-    ngDevMode && assertIndexInRange(lView, insertBeforeIndex);
-    return unwrapRNode(lView[insertBeforeIndex]);
+  return _getInsertInFrontOfRNodeWithI18n(parentTNode, currentTNode, lView);
+}
+
+
+/**
+ * Find a node in front of which `currentTNode` should be inserted. (Does not take i18n into
+ * account)
+ *
+ * This method determines the `RNode` in front of which we should insert the `currentRNode`. This
+ * does not take `TNode.insertBeforeIndex` into account.
+ *
+ * @param parentTNode parent `TNode`
+ * @param currentTNode current `TNode` (The node which we would like to insert into the DOM)
+ * @param lView current `LView`
+ */
+export function getInsertInFrontOfRNodeWithNoI18n(
+    parentTNode: TNode, currentTNode: TNode, lView: LView): RNode|null {
+  if (parentTNode.type & (TNodeType.ElementContainer | TNodeType.Icu)) {
+    return getNativeByTNode(parentTNode, lView);
   }
   return null;
 }
 
+/**
+ * Tree shakable boundary for `getInsertInFrontOfRNodeWithI18n` function.
+ *
+ * This function will only be set if i18n code runs.
+ */
+let _getInsertInFrontOfRNodeWithI18n: (parentTNode: TNode, currentTNode: TNode, lView: LView) =>
+    RNode | null = getInsertInFrontOfRNodeWithNoI18n;
+
+/**
+ * Tree shakable boundary for `processI18nInsertBefore` function.
+ *
+ * This function will only be set if i18n code runs.
+ */
+let _processI18nInsertBefore: (
+    renderer: Renderer3, childTNode: TNode, lView: LView, childRNode: RNode|RNode[],
+    parentRElement: RElement|null) => void;
+
+export function setI18nHandling(
+    getInsertInFrontOfRNodeWithI18n: (parentTNode: TNode, currentTNode: TNode, lView: LView) =>
+        RNode | null,
+    processI18nInsertBefore: (
+        renderer: Renderer3, childTNode: TNode, lView: LView, childRNode: RNode|RNode[],
+        parentRElement: RElement|null) => void) {
+  _getInsertInFrontOfRNodeWithI18n = getInsertInFrontOfRNodeWithI18n;
+  _processI18nInsertBefore = processI18nInsertBefore;
+}
+
 /**
  * Appends the `child` native node (or a collection of nodes) to the `parent`.
  *
@@ -685,50 +721,8 @@ export function appendChild(
     }
   }
 
-  const tNodeInsertBeforeIndex = childTNode.insertBeforeIndex;
-  if (Array.isArray(tNodeInsertBeforeIndex) &&
-      (childTNode.flags & TNodeFlags.isComponentHost) === 0) {
-    // An array indicates that there are i18n nodes that need to be added as children of this
-    // `rChildNode`. These i18n nodes were created before this `rChildNode` was available and so
-    // only now can be added. The first element of the array is the normal index where we should
-    // insert the `rChildNode`. Additional elements are the extra nodes to be added as children of
-    // `rChildNode`.
-    processI18nText(renderer, childTNode, lView, childRNode, parentRNode, tNodeInsertBeforeIndex);
-  }
-}
-
-/**
- * Process `TNode.insertBeforeIndex` by adding i18n text nodes.
- *
- * See `TNode.insertBeforeIndex`
- *
- * @param renderer
- * @param childTNode
- * @param lView
- * @param childRNode
- * @param parentRElement
- * @param i18nChildren
- */
-function processI18nText(
-    renderer: Renderer3, childTNode: TNode, lView: LView, childRNode: RNode|RNode[],
-    parentRElement: RElement|null, i18nChildren: number[]): void {
-  ngDevMode && assertDomNode(childRNode);
-  const isProcedural = isProceduralRenderer(renderer);
-  let i18nParent: RElement|null = childRNode as RElement;
-  let anchorRNode: RNode|null = null;
-  if (!(childTNode.type & TNodeType.AnyRNode)) {
-    anchorRNode = i18nParent;
-    i18nParent = parentRElement;
-  }
-  const isViewRoot = childTNode.parent === null;
-  if (i18nParent !== null) {
-    for (let i = 1; i < i18nChildren.length; i++) {
-      // No need to `unwrapRNode` because all of the indexes point to i18n text nodes.
-      // see `assertDomNode` below.
-      const i18nChild = lView[i18nChildren[i]];
-      nativeInsertBefore(renderer, i18nParent, i18nChild, anchorRNode, false);
-    }
-  }
+  _processI18nInsertBefore !== undefined &&
+      _processI18nInsertBefore(renderer, childTNode, lView, childRNode, parentRNode);
 }
 
 /**

packages/core/src/render3/node_manipulation_i18n.ts

@@ -0,0 +1,72 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {assertDomNode, assertIndexInRange} from '../util/assert';
+import {TNode, TNodeFlags, TNodeType} from './interfaces/node';
+import {RElement, Renderer3, RNode} from './interfaces/renderer';
+import {LView} from './interfaces/view';
+import {getInsertInFrontOfRNodeWithNoI18n, nativeInsertBefore} from './node_manipulation';
+import {unwrapRNode} from './util/view_utils';
+
+
+/**
+ * Find a node in front of which `currentTNode` should be inserted (takes i18n into account).
+ *
+ * This method determines the `RNode` in front of which we should insert the `currentRNode`. This
+ * takes `TNode.insertBeforeIndex` into account.
+ *
+ * @param parentTNode parent `TNode`
+ * @param currentTNode current `TNode` (The node which we would like to insert into the DOM)
+ * @param lView current `LView`
+ */
+export function getInsertInFrontOfRNodeWithI18n(
+    parentTNode: TNode, currentTNode: TNode, lView: LView): RNode|null {
+  const tNodeInsertBeforeIndex = currentTNode.insertBeforeIndex;
+  const insertBeforeIndex =
+      Array.isArray(tNodeInsertBeforeIndex) ? tNodeInsertBeforeIndex[0] : tNodeInsertBeforeIndex;
+  if (insertBeforeIndex === null) {
+    return getInsertInFrontOfRNodeWithNoI18n(parentTNode, currentTNode, lView);
+  } else {
+    ngDevMode && assertIndexInRange(lView, insertBeforeIndex);
+    return unwrapRNode(lView[insertBeforeIndex]);
+  }
+}
+
+
+/**
+ * Process `TNode.insertBeforeIndex` by adding i18n text nodes.
+ *
+ * See `TNode.insertBeforeIndex`
+ */
+export function processI18nInsertBefore(
+    renderer: Renderer3, childTNode: TNode, lView: LView, childRNode: RNode|RNode[],
+    parentRElement: RElement|null): void {
+  const tNodeInsertBeforeIndex = childTNode.insertBeforeIndex;
+  if (Array.isArray(tNodeInsertBeforeIndex)) {
+    // An array indicates that there are i18n nodes that need to be added as children of this
+    // `childRNode`. These i18n nodes were created before this `childRNode` was available and so
+    // only now can be added. The first element of the array is the normal index where we should
+    // insert the `childRNode`. Additional elements are the extra nodes to be added as children of
+    // `childRNode`.
+    ngDevMode && assertDomNode(childRNode);
+    let i18nParent: RElement|null = childRNode as RElement;
+    let anchorRNode: RNode|null = null;
+    if (!(childTNode.type & TNodeType.AnyRNode)) {
+      anchorRNode = i18nParent;
+      i18nParent = parentRElement;
+    }
+    if (i18nParent !== null && (childTNode.flags & TNodeFlags.isComponentHost) === 0) {
+      for (let i = 1; i < tNodeInsertBeforeIndex.length; i++) {
+        // No need to `unwrapRNode` because all of the indexes point to i18n text nodes.
+        // see `assertDomNode` below.
+        const i18nChild = lView[tNodeInsertBeforeIndex[i]];
+        nativeInsertBefore(renderer, i18nParent, i18nChild, anchorRNode, false);
+      }
+    }
+  }
+}

packages/core/test/bundling/hello_world/bundle.golden_symbols.json

@@ -232,5 +232,8 @@
   },
   {
     "name": "viewAttachedToChangeDetector"
+  },
+  {
+    "name": "ɵɵtext"
   }
 ]