adds chapter 6.8 - http methods API

Author: ishtms

chapters/ch06.8-adding-verbs-api.md

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+## Adding HTTP methods to the Router
+
+In this exercise, we will improve our `TrieRouter` API by implementing support for HTTP verbs (GET, POST, PUT, DELETE, etc.) directly instead of using raw strings. Let's look at our current implementation of the `TrieRouter`:
+
+```js
+trieRouter.addRoute("GET", "/users", () => {});
+trieRouter.addRoute("GET", "/", () => {});
+```
+
+As you could already feel, this approach is not very flexible and uses raw strings, which can lead to typing errors, and has no auto-completion support unfortunately. Let's improve this by adding support for HTTP methods directly to the `TrieRouter` API.
+
+Firstly, we've added dedicated methods for each HTTP method in the `TrieRouter` class. This allows users to define routes more intuitively using method-specific calls like `trieRouter.get('/home', handler)` for the GET method and `trieRouter.post('/home', handler)` for the POST method.
+
+### Update the `TrieRouter` class
+
+```js
+const HTTP_METHODS = { ... };
+
+class TrieRouter {
+    ...
+
+    #addRoute(path, method, handler) {
+    ...
+    }
+
+    get(path, handler) {
+        this.#addRoute(path, HTTP_METHODS.GET, handler);
+    }
+
+    post(path, handler) {
+        this.#addRoute(path, HTTP_METHODS.POST, handler);
+    }
+
+    put(path, handler) {
+        this.#addRoute(path, HTTP_METHODS.PUT, handler);
+    }
+
+    delete(path, handler) {
+        this.#addRoute(path, HTTP_METHODS.DELETE, handler);
+    }
+
+    patch(path, handler) {
+        this.#addRoute(path, HTTP_METHODS.PATCH, handler);
+    }
+
+    head(path, handler) {
+        this.#addRoute(path, HTTP_METHODS.HEAD, handler);
+    }
+
+    options(path, handler) {
+        this.#addRoute(path, HTTP_METHODS.OPTIONS, handler);
+    }
+
+    connect(path, handler) {
+        this.#addRoute(path, HTTP_METHODS.CONNECT, handler);
+    }
+
+    trace(path, handler) {
+        this.#addRoute(path, HTTP_METHODS.TRACE, handler);
+    }
+    ...
+}
+```
+
+Firstly, we've added dedicated methods for each HTTP method in the `TrieRouter` class. This allows users to define routes more intuitively using method-specific calls like `trieRouter.get('/home', handler)` for the GET method and `trieRouter.post('/home', handler)` for the POST method.
+
+In each of these methods, we call the existing `addRoute` method, passing the appropriate HTTP method from the `HTTP_METHODS` object.
+
+This change allows for a consistent and clear way to find routes based on the HTTP method.
+
+Sedcondly, we've made the `addRoute` method private by prefixing it with a `#`. This means that the `#addRoute` method can now only be accessed from within the `TrieRouter` class and not from outside.
+
+Now, to test the new API, let's update our previous example:
+
+```js
+const trieRouter = new TrieRouter();
+
+trieRouter.get("/users", function get1() {});
+trieRouter.post("/users", function post1() {});
+trieRouter.put("/users", function put1() {});
+trieRouter.delete("/users", function delete1() {});
+
+console.log(trieRouter.findRoute("/users/e", HTTP_METHODS.GET)); // null
+console.log(trieRouter.findRoute("/users", HTTP_METHODS.POST)); // function post1() {}
+console.log(trieRouter.findRoute("/users", HTTP_METHODS.PUT)); // function put1() {}
+console.log(trieRouter.findRoute("/users", HTTP_METHODS.TRACE)); // undefined
+```
+
+Looks good, and now we have a more intuitive way to define routes based on HTTP methods. Let's move on to the next exercise to add support for route parameters.