From 3237e6947c23d5269e04443c41d33f748b36ae54 Mon Sep 17 00:00:00 2001
From: Klaus Meinhardt <klaus.meinhardt1@gmail.com>
Date: Mon, 7 Aug 2017 23:50:32 +0200
Subject: [PATCH] prefer-object-spread: add parens in shorthand arrow function
 (#3026)

---
 src/rules/preferObjectSpreadRule.ts          | 5 +++--
 test/rules/prefer-object-spread/test.ts.fix  | 2 ++
 test/rules/prefer-object-spread/test.ts.lint | 4 +++-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/rules/preferObjectSpreadRule.ts b/src/rules/preferObjectSpreadRule.ts
index 917063cc9e2..5bcaa7b0ee6 100644
--- a/src/rules/preferObjectSpreadRule.ts
+++ b/src/rules/preferObjectSpreadRule.ts
@@ -65,9 +65,10 @@ function walk(ctx: Lint.WalkContext<void>) {
 
 function createFix(node: ts.CallExpression, sourceFile: ts.SourceFile): Lint.Fix {
     const args = node.arguments;
+    const objectNeedsParens = node.parent!.kind === ts.SyntaxKind.ArrowFunction;
     const fix = [
-        Lint.Replacement.replaceFromTo(node.getStart(sourceFile), args[0].getStart(sourceFile), "{"),
-        new Lint.Replacement(node.end - 1, 1, "}"),
+        Lint.Replacement.replaceFromTo(node.getStart(sourceFile), args[0].getStart(sourceFile), `${objectNeedsParens ? "(" : ""}{`),
+        new Lint.Replacement(node.end - 1, 1, `}${objectNeedsParens ? ")" : ""}`),
     ];
     for (let i = 0; i < args.length; ++i) {
         const arg = args[i];
diff --git a/test/rules/prefer-object-spread/test.ts.fix b/test/rules/prefer-object-spread/test.ts.fix
index 324bf2cb634..a7c870277e3 100644
--- a/test/rules/prefer-object-spread/test.ts.fix
+++ b/test/rules/prefer-object-spread/test.ts.fix
@@ -23,3 +23,5 @@ result = Object.assign(new Foo(), {});
 result = Object.assign(createFoo(), {});
 result = Object.assign(function() {}, {});
 result = Object.assign(() => {}, {});
+
+let fn = () => ({...original});
diff --git a/test/rules/prefer-object-spread/test.ts.lint b/test/rules/prefer-object-spread/test.ts.lint
index 0786e1fefcf..a11c62ad914 100644
--- a/test/rules/prefer-object-spread/test.ts.lint
+++ b/test/rules/prefer-object-spread/test.ts.lint
@@ -37,5 +37,7 @@ result = Object.assign(createFoo(), {});
 result = Object.assign(function() {}, {});
 result = Object.assign(() => {}, {});
 
+let fn = () => Object.assign({}, original);
+               ~~~~~~~~~~~~~~~~~~~~~~~~~~~ [0]
 [0]: Use the object spread operator instead.
-[1]: 'Object.assign' returns the first argument. Prefer object spread if you want a new object.
\ No newline at end of file
+[1]: 'Object.assign' returns the first argument. Prefer object spread if you want a new object.