From 64df0efcca238e2ebb2ba1e246e9820c01df0fbf Mon Sep 17 00:00:00 2001
From: Alex Rickabaugh <alx+alxhub@alxandria.net>
Date: Thu, 22 Dec 2022 11:57:20 -0500
Subject: [PATCH] refactor(compiler): pipeline phase to lift element attributes
 into const arrays (#48580)

This commit serializes the attributes on element-like structures in the template
and converts them to constant arrays, which it lifts into the `consts` array for
the entire component compilation.

PR Close #48580
---
 .../pipeline/src/phases/const_collection.ts   | 62 +++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 packages/compiler/src/template/pipeline/src/phases/const_collection.ts

diff --git a/packages/compiler/src/template/pipeline/src/phases/const_collection.ts b/packages/compiler/src/template/pipeline/src/phases/const_collection.ts
new file mode 100644
index 00000000000..b7430ad6564
--- /dev/null
+++ b/packages/compiler/src/template/pipeline/src/phases/const_collection.ts
@@ -0,0 +1,62 @@
+/**
+ * @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 * as core from '../../../../core';
+import * as o from '../../../../output/output_ast';
+import * as ir from '../../ir';
+import {ElementAttributes} from '../../ir/src/element';
+import {ComponentCompilation} from '../compilation';
+
+/**
+ * Converts the semantic attributes of element-like operations (elements, templates) into constant
+ * array expressions, and lifts them into the overall component `consts`.
+ */
+export function phaseConstCollection(cpl: ComponentCompilation): void {
+  for (const [_, view] of cpl.views) {
+    for (const op of view.create) {
+      if (op.kind !== ir.OpKind.ElementStart && op.kind !== ir.OpKind.Element &&
+          op.kind !== ir.OpKind.Template) {
+        continue;
+      } else if (!(op.attributes instanceof ElementAttributes)) {
+        continue;
+      }
+
+      const attrArray = serializeAttributes(op.attributes);
+      if (attrArray.entries.length > 0) {
+        op.attributes = cpl.addConst(attrArray);
+      } else {
+        op.attributes = null;
+      }
+    }
+  }
+}
+
+function serializeAttributes({attributes, bindings, classes, i18n, projectAs, styles, template}:
+                                 ElementAttributes): o.LiteralArrayExpr {
+  const attrArray = [...attributes];
+
+  if (projectAs !== null) {
+    attrArray.push(o.literal(core.AttributeMarker.ProjectAs), o.literal(projectAs));
+  }
+  if (classes.length > 0) {
+    attrArray.push(o.literal(core.AttributeMarker.Classes), ...classes);
+  }
+  if (styles.length > 0) {
+    attrArray.push(o.literal(core.AttributeMarker.Styles), ...styles);
+  }
+  if (bindings.length > 0) {
+    attrArray.push(o.literal(core.AttributeMarker.Bindings), ...bindings);
+  }
+  if (template.length > 0) {
+    attrArray.push(o.literal(core.AttributeMarker.Template), ...template);
+  }
+  if (i18n.length > 0) {
+    attrArray.push(o.literal(core.AttributeMarker.I18n), ...i18n);
+  }
+  return o.literalArr(attrArray);
+}