From 58d52df7c45a6c7b7c12fbf1f0b1f341c3d61e3c Mon Sep 17 00:00:00 2001
From: Dylan Hunn <dylhunn@gmail.com>
Date: Tue, 10 Oct 2023 16:46:17 -0700
Subject: [PATCH] feat(language-service): Complete inside @switch

We now visit the unknown nodes inside a `@switch` block, enabling completions in that context.
---
 packages/language-service/src/completions.ts  | 23 +++++++++++--------
 .../language-service/src/template_target.ts   |  1 +
 .../language-service/test/completions_spec.ts |  9 ++++++++
 3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/packages/language-service/src/completions.ts b/packages/language-service/src/completions.ts
index d64cac480bdd4..006f8fcc9ed5d 100644
--- a/packages/language-service/src/completions.ts
+++ b/packages/language-service/src/completions.ts
@@ -9,7 +9,7 @@
 import {AST, ASTWithSource, BindingPipe, BindingType, Call, EmptyExpr, ImplicitReceiver, LiteralPrimitive, ParsedEventType, ParseSourceSpan, PropertyRead, PropertyWrite, SafePropertyRead, TmplAstBoundAttribute, TmplAstBoundEvent, TmplAstElement, TmplAstNode, TmplAstReference, TmplAstTemplate, TmplAstText, TmplAstTextAttribute, TmplAstVariable} from '@angular/compiler';
 import {NgCompiler} from '@angular/compiler-cli/src/ngtsc/core';
 import {CompletionKind, PotentialDirective, SymbolKind, TemplateDeclarationSymbol} from '@angular/compiler-cli/src/ngtsc/typecheck/api';
-import {BoundEvent, DeferredBlock, TextAttribute, UnknownBlock} from '@angular/compiler/src/render3/r3_ast';
+import {BoundEvent, DeferredBlock, SwitchBlock, TextAttribute, UnknownBlock} from '@angular/compiler/src/render3/r3_ast';
 import ts from 'typescript';
 
 import {addAttributeCompletionEntries, AsciiSortPriority, AttributeCompletionKind, buildAnimationCompletionEntries, buildAttributeCompletionTable, getAttributeCompletionSymbol} from './attribute_completions';
@@ -130,15 +130,18 @@ export class CompletionBuilder<N extends TmplAstNode|AST> {
         length: this.node.name.length,
       }
     };
-    const completionEntries: ts.CompletionEntry[] = [
-      ...blocksWithParens, ...blocksWithoutParens
-    ].map(name => ({
-            name,
-            sortText: `${AsciiSortPriority.First}${name}`,
-            insertText: buildBlockSnippet(useSnippet, name, blocksWithParens.includes(name)),
-            isSnippet: useSnippet || undefined,
-            ...partialCompletionEntryWholeBlock,
-          }));
+    let competionKeywords: string[] = [...blocksWithParens, ...blocksWithoutParens];
+    if (this.nodeParent instanceof SwitchBlock) {
+      competionKeywords = ['case', 'default'];
+    }
+    const completionEntries: ts.CompletionEntry[] = competionKeywords.map(
+        name => ({
+          name,
+          sortText: `${AsciiSortPriority.First}${name}`,
+          insertText: buildBlockSnippet(useSnippet, name, blocksWithParens.includes(name)),
+          isSnippet: useSnippet || undefined,
+          ...partialCompletionEntryWholeBlock,
+        }));
 
     // Return the completions.
     const completionInfo: ts.CompletionInfo = {
diff --git a/packages/language-service/src/template_target.ts b/packages/language-service/src/template_target.ts
index 3ddbc7da14ff8..bed3337dd7889 100644
--- a/packages/language-service/src/template_target.ts
+++ b/packages/language-service/src/template_target.ts
@@ -499,6 +499,7 @@ class TemplateTargetVisitor implements t.Visitor {
   visitSwitchBlock(block: t.SwitchBlock) {
     this.visitBinding(block.expression);
     this.visitAll(block.cases);
+    this.visitAll(block.unknownBlocks);
   }
 
   visitSwitchBlockCase(block: t.SwitchBlockCase) {
diff --git a/packages/language-service/test/completions_spec.ts b/packages/language-service/test/completions_spec.ts
index 47c2619bb270e..038c026b99162 100644
--- a/packages/language-service/test/completions_spec.ts
+++ b/packages/language-service/test/completions_spec.ts
@@ -298,6 +298,15 @@ describe('completions', () => {
           completions, unsafeCastDisplayInfoKindToScriptElementKind(DisplayInfoKind.BLOCK),
           ['switch']);
     });
+
+    it('inside switch', () => {
+      const {templateFile} = setup(`@switch (1) { @c }`, ``);
+      templateFile.moveCursorToText('@c¦');
+      const completions = templateFile.getCompletionsAtPosition();
+      expectContain(
+          completions, unsafeCastDisplayInfoKindToScriptElementKind(DisplayInfoKind.BLOCK),
+          ['case']);
+    });
   });
 
   describe('in an expression scope', () => {