feat: Add response data callbacks

It is now possible to register callbacks that can read and modify
the actual response json (or the empty response base structure on
requests not returning any response (e.g. delete)

Author: eFrane

Changelog.md

@@ -1,5 +1,8 @@
 # next version
 
+- **BREAKING**: Success and error callbacks can no longer modify the response data,
+  to act on the parsed response data for all requests you **MUST** use
+  `ResourcefulApi`'s new `responseCallback`s.
 - The `deleteAction` **can** be passed
   a full query now, this brings it in alignment with
   the other actions.

src/api/ResourcefulApi.js

@@ -8,6 +8,30 @@ import { deref, hasOwn } from '../shared/utils'
 import { Performance } from '../shared/Performance'
 
 export class ResourcefulApi extends Api {
+  constructor () {
+    super()
+
+    /** @var {Function[]} */
+    this.responseCallbacks = []
+  }
+
+  /**
+   * Functions to be called with the parsed request data.
+   *
+   * @param {Function[]} callbacks
+   */
+  setResponseCallbacks (callbacks) {
+    this.responseCallbacks = callbacks
+  }
+
+  addResponseCallback (cb) {
+    this.responseCallbacks.push(cb)
+  }
+
+  resetResponseCallbacks () {
+    this.responseCallbacks = []
+  }
+
   /**
    * Extends `Api::doRequest()` to handle some data preprocessing.
    *
@@ -27,13 +51,19 @@ export class ResourcefulApi extends Api {
 
     return super._doRequest(method, url, params, data)
       .then(async (response) => {
+        let parsedResponse = this._createDatalessResponse(response)
+
         if (this._shouldDecodeResponseJson(response.status)) {
           const json = await this._decodeResponseJson(response)
 
-          return this._parseResponse(response.status, json)
+          parsedResponse = this._parseResponse(response.status, json)
+        }
+
+        for (const cb of this.responseCallbacks) {
+          parsedResponse = cb(parsedResponse, response.status)
         }
 
-        return this._createDatalessResponse(response)
+        return Object.freeze(parsedResponse)
       })
   }
 

test/api/ResourcefulApi.spec.js

@@ -74,3 +74,30 @@ test('keeps null relationships after preprocessing', () => {
   const preprocessedData = api.preprocessData(testResource)
   expect(preprocessedData.data.relationships.hobbies.data).toBe(null)
 })
+
+test('runs response callbacks', async () => {
+  const api = new ResourcefulApi()
+  api.setBaseUrl('http://api/')
+  api.addResponseCallback((response, status) => {
+    response.status_on_response = status
+
+    return response
+  })
+
+  expect(await api.get('/book/1')).toMatchObject({
+    data: {
+      book: {
+        1: {
+          attributes: {
+            author: expect.any(String),
+            title: expect.any(String)
+          }
+        }
+      }
+    },
+    links: {},
+    meta: {},
+    status: 200,
+    status_on_response: 200
+  })
+})