some initial API refactoring

src/services/api/helpers.js

@@ -0,0 +1,87 @@
+import { RegistrationError, StatusCodeError } from 'src/services/errors/errors'
+
+export const promisedRequest = ({
+  method,
+  url,
+  params,
+  payload,
+  formData,
+  credentials,
+  headers = {},
+}) => {
+  const options = {
+    method,
+    credentials: 'same-origin',
+    headers: {
+      Accept: 'application/json',
+      ...headers,
+    },
+  }
+  if (!formData) {
+    options.headers['Content-Type'] = 'application/json'
+  }
+  if (params) {
+    url +=
+      '?' +
+      Object.entries(params)
+        .map(
+          ([key, value]) =>
+            encodeURIComponent(key) + '=' + encodeURIComponent(value),
+        )
+        .join('&')
+  }
+  if (formData || payload) {
+    options.body = formData || JSON.stringify(payload)
+  }
+
+  if (credentials) {
+    options.headers = {
+      ...options.headers,
+      ...authHeaders(credentials),
+    }
+  }
+
+  return fetch(url, options).then((response) => {
+    return new Promise((resolve, reject) => {
+      // 204 is "No content", which fails to parse json (as you'd might think)
+      if (response.ok && response.status === 204) resolve()
+
+      return response
+        .json()
+        .then((json) => {
+          if (!response.ok) {
+            return reject(
+              new StatusCodeError(
+                response.status,
+                json,
+                { url, options },
+                response,
+              ),
+            )
+          }
+
+          json._response = response
+
+          return resolve(json)
+        })
+        .catch((error) => {
+          return reject(
+            new StatusCodeError(
+              response.status,
+              error,
+              { url, options },
+              response,
+            ),
+          )
+        })
+    })
+  })
+}
+
+const authHeaders = (accessToken) => {
+  if (accessToken) {
+    return { Authorization: `Bearer ${accessToken}` }
+  } else {
+    return {}
+  }
+}