[feat] backend from global variable

Author: xbill82

README.md

@@ -65,6 +65,20 @@ For example, you can build your up to connect the Websocket to `wss://kuzzle.myd
 VUE_APP_BACKEND_HOST=kuzzle.mydomain.com VUE_APP_BACKEND_PORT=443 VUE_APP_BACKEND_SSL=true npm run build
 ```
 
+## Specify the backend via a global variable
+
+You can also specify the backend config as a JSON-stringified POJO living in a global variable called `kuzzleBackend`. This variable must be available _before_ the Vue app is started, specifically before the `instantiateKuzzleSDK` public function is called. Here is an example of how to declare it
+
+```javascript
+const kuzzleBackend = JSON.stringify({
+  host: 'myhost.mydomain.com',
+  options: {
+    port: 443,
+    ssl: true
+  }
+})
+```
+
 ## Specify the backend via localStorage
 
 _Purely for debug purposes_, you can override all the backend configuration by setting your backend as stringified JSON in the `kuzzle-backend` Local Storage item, e.g.
@@ -75,6 +89,15 @@ _Purely for debug purposes_, you can override all the backend configuration by s
 
 **Beware that Local Storage is persistent and it is fairly easy to forget you set this item.** Use it consciously and keep in mind it is a good practice to unset it as soon as your debug session is over.
 
+## Backend declaration precedence order
+
+The plugin makes a choice of the available backend declaration by setting a preference order.
+
+* Local storage (`kuzzle-backend`)
+* Global variable (`kuzzleBackend`)
+* Environment variables
+* Options passed to `Vue.use`
+
 ## Accessing the Kuzzle SDK instance within the app
 
 You'll be able to access the Kuzzle SDK instance from the components as

index.ts

@@ -2,6 +2,7 @@ import { Kuzzle, WebSocket } from 'kuzzle-sdk';
 import _Vue  from 'vue';
 
 const LS_KEY = 'kuzzle-backend'
+const GLOBAL_NAME = 'kuzzleBackend'
 
 interface Backend {
   host: string;
@@ -52,8 +53,22 @@ export function getBackendFromLocalStorage() {
   return backend;
 }
 
+export function getBackendFromWindow() {
+  if (!window[GLOBAL_NAME]) {
+    return null
+  }
+
+  const backend = JSON.parse(window[GLOBAL_NAME])
+
+  if (typeof backend !== 'object') {
+    throw new Error(`Item found in global (${GLOBAL_NAME}) is malformed. Expected an object, found ${backend}`)
+  }
+
+  return backend;
+}
+
 export const instantiateKuzzleSDK = (backendsConfig: Backends, sdkOptions: any): Kuzzle => {
-  const backend:Backend | null = getBackendFromLocalStorage() || getBackendFromConf(backendsConfig)
+  const backend:Backend | null = getBackendFromLocalStorage() || getBackendFromWindow() || getBackendFromConf(backendsConfig)
 
   if (!backend) {
     throw new Error('No backend resolved.');

package.json

@@ -1,6 +1,6 @@
 {
   "name": "vue-plugin-kuzzle",
-  "version": "4.2.0",
+  "version": "4.3.0",
   "description": "A Vuejs plugin shipping the Kuzzle SDK in your components",
   "main": "index.js",
   "types": "./index.d.ts",