Merge #731

731: Fix double slash error and refactor api routes r=bidoubiwa a=bidoubiwa

In this PR is linked to #652. This issue raises the problem where the requested URL has a double slash. This does not impact the usability of meilisearch-js but could potentially become a problem. Also the error handler shows clearly the double slash when a communication error occurs. 

To avoid this problem in the future this PR does the following: 
- REFACTO: Removed all starting slashes on sub-routes in the code
- FIX: Add multiple check inside the http handler for the following cases: 
    - If the pathname ends with a slash OR if the sub-route start with a slash, we do not add a slash
    - If the pathname ends with a slash AND if the sub-routes start with a slash, we remove the starting slash in the sub route
    - If the sub-routes ends with a slash, remove that slash for consistency  in URL request (ex: you could have the following requests: `http://localhost:7700/indexes/` and `http://localhost:7700/stats` both url are not consistent in their trailing slash)
    - if the pathname ends with two slashes, remove one.
- REFACTO: Center all routes at the start of both the Index and MeilISearch class. In order to have a better visibility on the different routes and to avoid having to scroll to find how a specific route was hard coded.

Some design choices: 
- You might ask why I kept `const url = ...` instead of directly adding the result in the returned function. I chose that for readability. If you think it is a bad idea tell me so. 
- The static lists that are at the top of each class tries to not repeat itself. Maybe it should repeat itself for readibility purposes. If you think the way I made it is not readable feel free to tell me. Also if you think they should be in another file feel free to also tell me. 

 This PR  tests are failing  ❌ because  of an update on slash handling. Working tests are here #732. They need to be merged here for this PR to pass its tests.
fixes: #731 #744 

Co-authored-by: Charlotte Vermandel <[email protected]>
Co-authored-by: cvermand <[email protected]>

Author: bors[bot]

src/http-requests.ts

@@ -7,15 +7,22 @@ import {
 
 class HttpRequests {
   headers: {}
-  url: string
+  url: URL
 
   constructor(config: Types.Config) {
     this.headers = {
       ...(config.headers || {}),
       'Content-Type': 'application/json',
       ...(config.apiKey ? { 'X-Meili-API-Key': config.apiKey } : {}),
     }
-    this.url = config.host
+    this.url = new URL(config.host)
+  }
+
+  static addTrailingSlash(url: string): string {
+    if (!url.endsWith('/')) {
+      url += '/'
+    }
+    return url
   }
 
   async request({
@@ -32,17 +39,14 @@ class HttpRequests {
     config?: Partial<Request>
   }) {
     try {
-      const constructURL = new URL(this.url)
-      constructURL.pathname = constructURL.pathname + url
-
+      const constructURL = new URL(url, this.url)
       if (params) {
         const queryParams = new URLSearchParams()
         Object.keys(params)
           .filter((x: string) => params[x] !== null)
           .map((x: string) => queryParams.set(x, params[x]))
         constructURL.search = queryParams.toString()
       }
-
       const response: Response = await fetch(constructURL.toString(), {
         ...config,
         method,