From 72f8abd7b30290e58f6951a109009615e1e80445 Mon Sep 17 00:00:00 2001
From: Trotyl <trotyl@qq.com>
Date: Mon, 12 Feb 2018 00:02:24 +0800
Subject: [PATCH] fix(compiler): make unary plus operator consistent to
 JavaScript (#22154)

fixes #22089

PR Close #22154
---
 packages/compiler/src/expression_parser/parser.ts       | 4 +++-
 packages/compiler/test/expression_parser/parser_spec.ts | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/packages/compiler/src/expression_parser/parser.ts b/packages/compiler/src/expression_parser/parser.ts
index 93d2362a43..55d6b40514 100644
--- a/packages/compiler/src/expression_parser/parser.ts
+++ b/packages/compiler/src/expression_parser/parser.ts
@@ -477,7 +477,9 @@ export class _ParseAST {
       switch (operator) {
         case '+':
           this.advance();
-          return this.parsePrefix();
+          result = this.parsePrefix();
+          return new Binary(
+              this.span(start), '-', result, new LiteralPrimitive(new ParseSpan(start, start), 0));
         case '-':
           this.advance();
           result = this.parsePrefix();
diff --git a/packages/compiler/test/expression_parser/parser_spec.ts b/packages/compiler/test/expression_parser/parser_spec.ts
index 0d08b4b4a1..cdd38fb72f 100644
--- a/packages/compiler/test/expression_parser/parser_spec.ts
+++ b/packages/compiler/test/expression_parser/parser_spec.ts
@@ -103,7 +103,9 @@ import {validate} from './validator';
 
       it('should parse unary - expressions', () => {
         checkAction('-1', '0 - 1');
-        checkAction('+1', '1');
+        checkAction('+1', '1 - 0');
+        checkAction(`-'1'`, `0 - "1"`);
+        checkAction(`+'1'`, `"1" - 0`);
       });
 
       it('should parse unary ! expressions', () => {