From fd1bbbf367d3d01a7f3c1d87408a7c765721daa4 Mon Sep 17 00:00:00 2001
From: Tanguy Krotoff <tkrotoff@gmail.com>
Date: Sat, 19 Nov 2016 12:56:37 +0100
Subject: [PATCH] Allow Body.json() typed result

---
 whatwg-fetch/index.d.ts            |  2 +-
 whatwg-fetch/whatwg-fetch-tests.ts | 38 +++++++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/whatwg-fetch/index.d.ts b/whatwg-fetch/index.d.ts
index f17d88a7df..c3667ae402 100644
--- a/whatwg-fetch/index.d.ts
+++ b/whatwg-fetch/index.d.ts
@@ -34,7 +34,7 @@ interface Body {
     arrayBuffer(): Promise<ArrayBuffer>;
     blob(): Promise<Blob>;
     formData(): Promise<FormData>;
-    json(): Promise<any>;
+    json<T>(): Promise<T>;
     text(): Promise<string>;
 }
 
diff --git a/whatwg-fetch/whatwg-fetch-tests.ts b/whatwg-fetch/whatwg-fetch-tests.ts
index aa6b90b8c8..2ad0f1ce43 100644
--- a/whatwg-fetch/whatwg-fetch-tests.ts
+++ b/whatwg-fetch/whatwg-fetch-tests.ts
@@ -68,4 +68,40 @@ function handlePromise(promise: Promise<Response>) {
 	}).then((text) => {
 		console.log(text);
 	});
-}
\ No newline at end of file
+}
+
+function test_Body_json() {
+	interface FooBar {
+		foo: string;
+		bar: string;
+	}
+
+	fetch('http://test.com')
+		.then(response => response.json<FooBar>())
+		.then(fooBar => {
+			console.log(fooBar.foo);
+			console.log(fooBar.bar);
+		});
+
+	fetch('http://test.com')
+		.then(response => <Promise<FooBar>> response.json())
+		.then(fooBar => {
+			console.log(fooBar.foo);
+			console.log(fooBar.bar);
+		});
+
+	fetch('http://test.com')
+		.then(response => response.json() as Promise<FooBar>)
+		.then(fooBar => {
+			console.log(fooBar.foo);
+			console.log(fooBar.bar);
+		});
+
+	fetch('http://test.com')
+		.then(response => response.json())
+		.then(fooBar => {
+			// fooBar is {}, not FooBar
+			//console.log(fooBar.foo);
+			//console.log(fooBar.bar);
+		});
+}