[mabel] Add more exercises and edits to Express.js lessons

Author: mabelleeyanhwa

docs/backend-web-development/express-param-processing.md

@@ -69,8 +69,4 @@ To define the parameter callbacks on a router instead, use `router.param`.
 ## Exercises
 
 Refactor the previous songs route to use `app.param` for the `id` parameter.
-Find the song of that particular id and put the song in the request object.
-
-```js
-req.song = song;
-```
+Find the song of that particular id and put the song in the request object as a property of the request object.

docs/backend-web-development/express-routers.md

@@ -197,3 +197,10 @@ Now we can support both API versions!
 
 What do you see when you go to http://localhost:3000/v1 on the browser?
 How about http://localhost:3000/v2 ?
+
+## Exercises
+
+Now that we have both movies and songs routes on the same App.js file, we should split them into a movies router and songs router.
+
+Make sure that the tests are passing as you refactor the routes.
+After refactoring the code to their individual routers, we shall refactor the tests to their individual test files too.

docs/backend-web-development/express-simple-server.md

@@ -50,9 +50,10 @@ app.delete("/", (req, res) => {
 
 ### cURL
 
-Client URL
-cURL is by default already installed in Mac OS. For Windows, you can download cURL separately.
-You can send different HTTP requests.
+cURL stands for Client URL.
+cURL is by default already installed in Mac OS. For Windows, if you have anything older than Windows 10 build 1706, you can download cURL separately. Else, you might already have cURL.
+
+You can send different HTTP requests using cURL.
 
 For example, let's send a POST request to https://localhost:3000/ with a JSON message body.
 

docs/backend-web-development/express-testing.md

@@ -234,6 +234,78 @@ describe("POST /", () => {
 });
 ```
 
+### Writing test for routes
+
+Let's see an example of writing an actual test for a route.
+
+We want to make a test for the following endpoint:
+
+POST /songs route of the songs API
+
+Test: POST /songs should return a new song object
+Route: POST /songs
+Expected response status code: 201
+Example request body:
+
+```json
+{ "name": "test movie", "artist": "rhianna" }
+```
+
+Example JSON response:
+
+```json
+{ "id": 1, "name": "test movie", "artist": "rhianna" }
+```
+
+```js
+it("POST /songs should add a song and return a new song object", async () => {
+  const newSong = { name: "test movie", artist: "rhianna" };
+  const expectedSong = { id: 1, name: "test movie", artist: "rhianna" };
+
+  const { response } = await request(app)
+    .post("/songs")
+    .send(newSong)
+    .expect(201);
+
+  expect(response.status).toEqual(201);
+  expect(response.body).toEqual(expectedSong);
+});
+```
+
+Could also be written as:
+
+```js
+it("POST /songs should add a song and return a new song object", async () => {
+  const newSong = { name: "test movie", artist: "rhianna" };
+  const expectedSong = { id: 1, name: "test movie", artist: "rhianna" };
+
+  const { body: actualSong } = await request(app)
+    .post("/songs")
+    .send(newSong)
+    .expect(201);
+
+  expect(actualSong).toEqual(expectedSong);
+});
+```
+
+### toMatchObject
+
+Sometimes, we do not want to test for an exact match for the response object. We are satisfied with having certain object properties. We can make use of a useful Jest method called `toMatchObject`.
+
+One possible use of this is for the GET /songs/:id route.
+
+```js
+  it("GET /songs/:id should return the correct song", () => {
+    const expectedSong = {name: "test song", artist: "rhianna"};
+
+    const {body: actualSong} = await request(app)
+    .get("/songs/1")
+    .expect(200)
+
+    expect(actualSong).toMatchObject(expectedSong);
+  });
+```
+
 ### Accessing agent in SuperTest
 
 ```js
@@ -262,6 +334,112 @@ There are some cases where we need to reuse the agent again. For example, we mig
 
 Check the [github page for supertest](https://github.com/visionmedia/supertest) for an example on how to access the agent in SuperTest and reuse the agent to persist a request and its cookies.
 
-## Exercises 
+## Exercises
+
+Add tests to the existing songs API we have been building.
+
+## TDD with Express.js
 
-Add tests to the songs API we have been building.
+Besides songs and the music industry, now our company would like to go into the movie industry. We need more routes on our API. They will now return movie information.
+
+Let's try TDD for movie routes.
+
+Add the tests for the movies endpoints.
+
+Test: POST /movies should return a new movie object
+Route: POST /movies
+Expected response status code: 201
+Example request body:
+
+```json
+{
+  "movieName": "Lion King"
+}
+```
+
+Example JSON response:
+
+```json
+{
+  "id": 1,
+  "movieName": "Lion King"
+}
+```
+
+Test: GET /songs should return an array containing one song
+Route: GET /movies
+Expected response status code: 200
+Example JSON response:
+
+```json
+[
+  {
+    "id": 1,
+    "movieName": "Lion King"
+  }
+]
+```
+
+Test: GET /movies/:id should return the movie with id
+Route: GET /movies/1
+Expected response status code: 200
+Example JSON response:
+
+```json
+{
+  "id": 1,
+  "movieName": "Lion King"
+}
+```
+
+Test: PUT /movies/:id should return the updated movie
+Route: PUT /movies/1
+Expected response status code: 200
+
+Example request body:
+
+```json
+{
+  "movieName": "Frozen 2"
+}
+```
+
+Example JSON response:
+
+```json
+{
+  "id": 1,
+  "movieName": "Frozen 2"
+}
+```
+
+Test: DELETE /movies/:id should return the deleted movie
+Route: DELETE /movies/1
+Expected response status code: 200
+
+Example request body:
+
+```json
+{
+  "movieName": "Frozen 2"
+}
+```
+
+Example JSON response:
+
+```json
+{
+  "id": 1,
+  "movieName": "Frozen 2"
+}
+```
+
+Test: GET /movies should return an empty array
+Route: GET /movies
+Expected response status code: 200
+
+Example JSON response:
+
+```json
+[]
+```

docs/backend-web-development/mongoose-middleware.md

@@ -14,12 +14,24 @@ For instance, models have `pre` and `post` functions that take two parameters:
 
 https://www.freecodecamp.org/news/introduction-to-mongoose-for-mongodb-d2a7aa593c57/
 
+## Hashing password with bcrypt
+
 Hashing user's password with bcrypt before saving to database.
 
 ```js
-userSchema.pre("save", async function(next) {
-  const rounds = 10;
-  this.password = await bcrypt.hash(this.password, rounds);
-  next();
+userSchema.pre("save", async function (next) {
+  if (this.isModified("password")) {
+    const rounds = 10;
+    this.password = await bcrypt.hash(this.password, rounds);
+    next();
+  }
 });
 ```
+
+https://mongoosejs.com/docs/api.html#document_Document-isModified
+
+Why should we check for `isModified`?
+
+`isModified` will only return true if you are changing the password or setting it for the first time.
+
+It will not be triggered, for example, if the user's name is changed.