First commit.

Signed-off-by: Chen Xiao <abigwc@gmail.com>

client/node_modules/d3-fetch/src/json.js

@@ -0,0 +1,9 @@
+function responseJson(response) {
+  if (!response.ok) throw new Error(response.status + " " + response.statusText);
+  if (response.status === 204 || response.status === 205) return;
+  return response.json();
+}
+
+export default function(input, init) {
+  return fetch(input, init).then(responseJson);
+}