From 10aba15154dc5e663318d6ff410f23a3f7502a1e Mon Sep 17 00:00:00 2001
From: ivanwonder <ivanwonder@outlook.com>
Date: Wed, 8 Jul 2020 16:29:55 +0800
Subject: [PATCH] fix(language-service): remove completion for string (#37983)

If the user inputs a string(e.g. `<div [ngClass]="'str~{cursor}'"></div>`), the completion is useless.

PR Close #37983
---
 packages/language-service/src/expressions.ts       | 11 ++++++++++-
 packages/language-service/test/completions_spec.ts |  7 +++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/packages/language-service/src/expressions.ts b/packages/language-service/src/expressions.ts
index 7eff222f58..f6cebc40d4 100644
--- a/packages/language-service/src/expressions.ts
+++ b/packages/language-service/src/expressions.ts
@@ -75,7 +75,16 @@ export function getExpressionCompletions(
     visitKeyedWrite(_ast) {},
     visitLiteralArray(_ast) {},
     visitLiteralMap(_ast) {},
-    visitLiteralPrimitive(_ast) {},
+    visitLiteralPrimitive(ast) {
+      // The type `LiteralPrimitive` include the `ERROR`, and it's wrapped as `string`.
+      // packages/compiler/src/template_parser/binding_parser.ts#L308
+      // So exclude the `ERROR` here.
+      if (typeof ast.value === 'string' &&
+          ast.value ===
+              templateInfo.source.slice(ast.sourceSpan.start + 1, ast.sourceSpan.end - 1)) {
+        result = undefined;
+      }
+    },
     visitMethodCall(_ast) {},
     visitPipe(ast) {
       if (position >= ast.exp.span.end &&
diff --git a/packages/language-service/test/completions_spec.ts b/packages/language-service/test/completions_spec.ts
index b5a818b656..d39324426f 100644
--- a/packages/language-service/test/completions_spec.ts
+++ b/packages/language-service/test/completions_spec.ts
@@ -848,6 +848,13 @@ describe('completions', () => {
     const completions = ngLS.getCompletionsAtPosition(TEST_TEMPLATE, marker.start);
     expect(completions).toBeUndefined();
   });
+
+  it('should not provide completions for string', () => {
+    mockHost.override(TEST_TEMPLATE, `<div [ngClass]="'str~{cursor}'"></div>`);
+    const marker = mockHost.getLocationMarkerFor(TEST_TEMPLATE, 'cursor');
+    const completions = ngLS.getCompletionsAtPosition(TEST_TEMPLATE, marker.start);
+    expect(completions).toBeUndefined();
+  });
 });
 
 function expectContain(