own function for fetch of config

src/actions/config.js

@@ -60,8 +60,8 @@ export function validateConfig(config) {
   return config;
 }
 
-function mergePreloadedConfig(preloadedConfig, fetchedConfig) {
-  const map = fromJS(fetchedConfig) || Map();
+function mergePreloadedConfig(preloadedConfig, loadedConfig) {
+  const map = fromJS(loadedConfig) || Map();
   return preloadedConfig ? preloadedConfig.mergeDeep(map) : map;
 }
 
@@ -75,12 +75,20 @@ function parseConfig(data) {
   return config;
 }
 
-async function getConfigFromResponse(response) {
-  const { status, headers } = response;
-  if (status === 200 && !headers.get('Content-Type').includes('text/html')) {
-    const config = await response.text();
-    return parseConfig(config);
+async function getConfig(file, isPreloaded) {
+  const response = await fetch(file, { credentials: 'same-origin' });
+  if (response.status !== 200) {
+    if (isPreloaded) return parseConfig('');
+    throw new Error(`Failed to load config.yml (${ response.status })`);
   }
+  const contentType = response.headers.get('Content-Type') || 'Not-Found';
+  const isYaml = contentType.indexOf('yaml') !== -1;
+  if (!isYaml) {
+    console.log(`Response for ${ file } was not yaml. (Content-Type: ${ contentType })`);
+    if (isPreloaded) return parseConfig('');
+    throw new Error('Failed to load configuration.');
+  }
+  return parseConfig(await response.text());
 }
 
 export function configLoaded(config) {
@@ -123,17 +131,12 @@ export function loadConfig() {
 
     try {
       const preloadedConfig = getState().config;
-      const response = await fetch('config.yml', { credentials: 'same-origin' })
-      const fetchedConfig = await getConfigFromResponse(response);
-
-      if (!preloadedConfig && !fetchedConfig) {
-        throw new Error(`Failed to load configuration.`);
-      }
+      const loadedConfig = await getConfig('config.yml', preloadedConfig && preloadedConfig.size > 1);
 
       /**
        * Merge any existing configuration so the result can be validated.
        */
-      const mergedConfig = mergePreloadedConfig(preloadedConfig, fetchedConfig)
+      const mergedConfig = mergePreloadedConfig(preloadedConfig, loadedConfig);
       const config = flow(validateConfig, applyDefaults)(mergedConfig);
 
       dispatch(configDidLoad(config));