Use proxy for all request methods other than GET (facebook#3726)

* Use proxy for all request methods other than GET * Add comment

Author: sidoshi

packages/react-dev-utils/WebpackDevServerUtils.js

@@ -317,15 +317,19 @@ function prepareProxy(proxy, appPublicFolder) {
  // For single page apps, we generally want to fallback to /index.html.
  // However we also want to respect `proxy` for API calls.
  // So if `proxy` is specified as a string, we need to decide which fallback to use.
- // We use a heuristic: if request `accept`s text/html, we pick /index.html.
+ // We use a heuristic: We want to proxy all the requests that are not meant
+ // for static assets and as all the requests for static assets will be using 
+ // `GET` method, we can proxy all non-`GET` requests.
+ // For `GET` requests, if request `accept`s text/html, we pick /index.html.
  // Modern browsers include text/html into `accept` header when navigating.
  // However API calls like `fetch()` won’t generally accept text/html.
  // If this heuristic doesn’t work well for you, use a custom `proxy` object.
  context: function(pathname, req) {
  return (
- mayProxy(pathname) &&
- req.headers.accept &&
- req.headers.accept.indexOf('text/html') === -1
+ req.method !== 'GET' ||
+ (mayProxy(pathname) &&
+ req.headers.accept &&
+ req.headers.accept.indexOf('text/html') === -1)
  );
  },
  onProxyReq: proxyReq => {