Make createFetch more readable

src/createFetch.js

@@ -7,28 +7,43 @@
  * LICENSE.txt file in the root directory of this source tree.
  */
 
-import isoFetch from 'isomorphic-fetch';
+/* @flow */
 
-type FetchOptions = {
+import fetch from 'isomorphic-fetch';
+
+type Options = {
   baseUrl: string,
   cookie?: string,
 };
 
-function createFetch({ baseUrl, cookie }: FetchOptions) {
-  return function fetch(url, options) {
-    const { headers, ...other } = options || {};
-    return url.startsWith('/') ? isoFetch(`${baseUrl}${url}`, {
-      method: 'POST',
+/**
+ * Creates a wrapper function around the HTML5 Fetch API that provides
+ * default arguments to fetch(...) and is intended to reduce the amount
+ * of boilerplate code in the application.
+ * https://developer.mozilla.org/docs/Web/API/Fetch_API/Using_Fetch
+ */
+function createFetch({ baseUrl, cookie }: Options) {
+  // NOTE: Tweak the default options to suite your application needs
+  const defaults = {
+    method: 'POST', // handy with GraphQL backends
+    mode: baseUrl ? 'cors' : 'same-origin',
+    credentials: baseUrl ? 'include' : 'same-origin',
+    headers: {
+      Accept: 'application/json',
+      'Content-Type': 'application/json',
+      ...(cookie ? { Cookie: cookie } : null),
+    },
+  };
+
+  return (url, options) => ((url.startsWith('/graphql') || url.startsWith('/api')) ?
+    fetch(`${baseUrl}${url}`, {
+      ...defaults,
+      ...options,
       headers: {
-        Accept: 'application/json',
-        'Content-Type': 'application/json',
-        ...(typeof cookie === 'undefined' ? null : { cookie }),
-        ...headers,
+        ...defaults.headers,
+        ...(options && options.headers),
       },
-      credentials: 'include',
-      ...other,
-    }) : isoFetch(url, options);
-  };
+    }) : fetch(url, options));
 }
 
 export default createFetch;

yarn.lock

@@ -2,6 +2,10 @@
 # yarn lockfile v1
 
 
+"@types/geojson@^1.0.0":
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/@types/geojson/-/geojson-1.0.2.tgz#b02d10ab028e2928ac592a051aaa4981a1941d03"
+
 JSONStream@^0.8.4:
   version "0.8.4"
   resolved "https://registry.yarnpkg.com/JSONStream/-/JSONStream-0.8.4.tgz#91657dfe6ff857483066132b4618b62e8f4887bd"
@@ -1313,8 +1317,8 @@ caniuse-api@^1.5.2:
     lodash.uniq "^4.5.0"
 
 caniuse-db@^1.0.30000187, caniuse-db@^1.0.30000529, caniuse-db@^1.0.30000634, caniuse-db@^1.0.30000639:
-  version "1.0.30000659"
-  resolved "https://registry.yarnpkg.com/caniuse-db/-/caniuse-db-1.0.30000659.tgz#6775220394d464c8efa4a25cafd2ed9b0c60b11c"
+  version "1.0.30000660"
+  resolved "https://registry.yarnpkg.com/caniuse-db/-/caniuse-db-1.0.30000660.tgz#d2d57b309dc5a11bb5b46018f51855f7a41efee5"
 
 caseless@~0.11.0:
   version "0.11.0"
@@ -3685,8 +3689,8 @@ jsonpointer@^4.0.0:
   resolved "https://registry.yarnpkg.com/jsonpointer/-/jsonpointer-4.0.1.tgz#4fd92cb34e0e9db3c89c8622ecf51f9b978c6cb9"
 
 jsonwebtoken@^7.3.0:
-  version "7.3.0"
-  resolved "https://registry.yarnpkg.com/jsonwebtoken/-/jsonwebtoken-7.3.0.tgz#85118d6a70e3fccdf14389f4e7a1c3f9c8a9fbba"
+  version "7.4.0"
+  resolved "https://registry.yarnpkg.com/jsonwebtoken/-/jsonwebtoken-7.4.0.tgz#515bf2bba070ec615bad97fd2e945027eb476946"
   dependencies:
     joi "^6.10.1"
     jws "^3.1.4"
@@ -6495,8 +6499,10 @@ terraformer-wkt-parser@^1.1.0:
     terraformer "~1.0.5"
 
 terraformer@~1.0.5:
-  version "1.0.7"
-  resolved "https://registry.yarnpkg.com/terraformer/-/terraformer-1.0.7.tgz#d8a19a56fbf25966ea062d21f515b93589702d69"
+  version "1.0.8"
+  resolved "https://registry.yarnpkg.com/terraformer/-/terraformer-1.0.8.tgz#51e0ad89746fcf2161dc6f65aa70e42377c8b593"
+  dependencies:
+    "@types/geojson" "^1.0.0"
 
 [email protected]:
   version "0.6.4"