From aaa08f7be3ab5170e597994480b10560c0752505 Mon Sep 17 00:00:00 2001
From: Pete Bacon Darwin <pete@bacondarwin.com>
Date: Tue, 22 Oct 2019 15:05:44 +0100
Subject: [PATCH] refactor(compiler): add abstract `NodeWithI18n` class to ML
 parsing (#33318)

This abstract class will be useful for identifying nodes that
can hold i18n data.

PR Close #33318
---
 packages/compiler/src/ml_parser/ast.ts | 34 +++++++++++++++++---------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/packages/compiler/src/ml_parser/ast.ts b/packages/compiler/src/ml_parser/ast.ts
index d0bdb8a21f..20e8343553 100644
--- a/packages/compiler/src/ml_parser/ast.ts
+++ b/packages/compiler/src/ml_parser/ast.ts
@@ -15,16 +15,24 @@ export interface Node {
   visit(visitor: Visitor, context: any): any;
 }
 
-export class Text implements Node {
-  constructor(public value: string, public sourceSpan: ParseSourceSpan, public i18n?: I18nMeta) {}
+export abstract class NodeWithI18n implements Node {
+  constructor(public sourceSpan: ParseSourceSpan, public i18n?: I18nMeta) {}
+  abstract visit(visitor: Visitor, context: any): any;
+}
+
+export class Text extends NodeWithI18n {
+  constructor(public value: string, sourceSpan: ParseSourceSpan, i18n?: I18nMeta) {
+    super(sourceSpan, i18n);
+  }
   visit(visitor: Visitor, context: any): any { return visitor.visitText(this, context); }
 }
 
-export class Expansion implements Node {
+export class Expansion extends NodeWithI18n {
   constructor(
       public switchValue: string, public type: string, public cases: ExpansionCase[],
-      public sourceSpan: ParseSourceSpan, public switchValueSourceSpan: ParseSourceSpan,
-      public i18n?: I18nMeta) {}
+      sourceSpan: ParseSourceSpan, public switchValueSourceSpan: ParseSourceSpan, i18n?: I18nMeta) {
+    super(sourceSpan, i18n);
+  }
   visit(visitor: Visitor, context: any): any { return visitor.visitExpansion(this, context); }
 }
 
@@ -36,18 +44,22 @@ export class ExpansionCase implements Node {
   visit(visitor: Visitor, context: any): any { return visitor.visitExpansionCase(this, context); }
 }
 
-export class Attribute implements Node {
+export class Attribute extends NodeWithI18n {
   constructor(
-      public name: string, public value: string, public sourceSpan: ParseSourceSpan,
-      public valueSpan?: ParseSourceSpan, public i18n?: I18nMeta) {}
+      public name: string, public value: string, sourceSpan: ParseSourceSpan,
+      public valueSpan?: ParseSourceSpan, i18n?: I18nMeta) {
+    super(sourceSpan, i18n);
+  }
   visit(visitor: Visitor, context: any): any { return visitor.visitAttribute(this, context); }
 }
 
-export class Element implements Node {
+export class Element extends NodeWithI18n {
   constructor(
       public name: string, public attrs: Attribute[], public children: Node[],
-      public sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan|null = null,
-      public endSourceSpan: ParseSourceSpan|null = null, public i18n?: I18nMeta) {}
+      sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan|null = null,
+      public endSourceSpan: ParseSourceSpan|null = null, i18n?: I18nMeta) {
+    super(sourceSpan, i18n);
+  }
   visit(visitor: Visitor, context: any): any { return visitor.visitElement(this, context); }
 }