basir/Amazona-FAQ.md

## Amazona-FAQ.md

      
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              Amazona-FAQ.md
            
          
    Amazona FAQ

If you can not find you question, put it as comment below. I will answer it and add it to the list.
Home Screen

TypeError: Cannot read property 'map' of undefined HomeScreen

It means that products is null.
check the value of products when loading = true, It should be empty array []
Also, check the value of products when loading = false, It should be products array.
If you are using redux, make sure that in the reducer you set the default value for products to an empty array.
function productListReducer(state = { products: [] }, action) {
...
}

Also in ProductScreen.js make sure you are checking loading === false && error === false when rendering products, otherwise you will get this error.
Cannot use import statement outside of a module

You did not set babel correctly to transpile ES6 code to ES5. Follow this:

npm install @babel/core, cli, node, preset-env
Create .babelrc

{ presets: [[“@babel/preset-env”]]}


Edit package.json

{
scripts:{
"start":"nodemon –exec babel-node server.js"
}

Localhost:3000/api/products 404 Error

You did not create res.get("/api/products") on server.js or you did not set proxy. check below for proxy setting.
Proxy error: could not proxy request /api/products

Check this:

frontend/package.json

{
  "name": "frontend",
  "proxy": "http://127.0.0.1:5000",
...
}


stop running frontend and backend
Run backend first

npm start


Then frontend

cd frontend
npm start

How to dynamically add categories in sidebar

You need to create an api for it. add this to productRoutes.js
router.get('/categories', asyncHandler(async (req, res) => {
  const categories = await Product.find().distinct('category');
  res.send(categories);
}));

Product Screen

Type Error: Can not read property name of undefined

const product = products.find(x => x._id = props.math.params.id);

it means that either products array is empty or the param id does not exist in the array. after find method check product is not null then render it.
Cart Screen

After logout cart still shows orders.

Edit userActions.js as follow:
const logout = () => (dispatch) => {
  Cookie.remove("userInfo");
 Cookie.remove("cartItems");
  dispatch({ type: USER_LOGOUT })
}

Invalid Token on click Place order buton

re-login. it fixes the error if you had a successful login before. it is because the token expires in 48h. you can change it in utils.js
Profile Screen

Cast to ObjectId failed for value "mine" at path "_id" for model "Order"

Move router.get("/mine") before router.get("/:id") in orderRoutes.js
Manage Products

Cannot read property 'token' of undefined

Make sure in frontend you supply token in ajax request
Authorization: `Bearer ${token}`

Also in backend utils.js you implemented isAuth and isAdmin like course source code
and in the productRoute.js you have this order:
router.post("/", isAuth, isAdmin, (req, res) => {

MongoDB

ServerDescription { address: 'localhost:27017' error: [MongoNetworkError]

You didn't install mongodb. Install it from here
Cannot load my localhost:5000/api/users/createadmin

You didn't install mongodb. Install it from here
E11000 duplicate key error collection: amazona.users index: email_1 dup key

You need to change the email in userRoutes.js method createAdmin to create a new admin.
Paypal

Not login to Paypal account

sandbox.paypal.com is a copy of paypal.com but you can only login here with sandbox accounts you created on the developer portal. More info here
Deploy

Error git add: you have another repo inside current repo

go to the frontend folder and delete the .git folder inside that. it should work.
Error in “rm -rf dist && babel backend -d dist”

In windows use this:
rm -rf` with `rmdir /s /q

why did you use eslint?

because it applies coding rules which your code consistent and elegant.
Error: ENOENT: no such file or directory, stat '\frontend\build\index.html'

you need to run
npm run build

then it works.
Heroku deploy steps


Create git repository

$ git init


Create Heroku Account and install Heroku CLI
Login on terminal and create app

$ heroku login
$ heroku apps:create amazonaapp


Edit package.json

script: {
 "build": "rm -rf dist && babel backend -d dist",
 "heroku-postbuild": "npm run build && cd frontend && npm install && npm run build"
 },
"engines": { "node": "12.4.0", "npm": "6.9.0"}


Create Procfile

web: node dist/server.js


Set Cloud MongoDB connection string

$ heroku config:set MONGODB_URL=<cloud mongodb connection string>


Edit config.js

PORT: process.env.PORT || 5000


Edit server.js

app.use(express.static(path.join(__dirname, '/../frontend/build')));
app.get('*', (req, res) => res.sendFile(path.join('${__dirname}/../frontend/build/index.html'));
app.listen(config.PORT, …)


Edit .babelrc

[
  "@babel/preset-env",
  {"targets": {"node": "current"}}
]


Commit and push

$ git add . && git commit -m "publish"
$ git push heroku

Create Cloud MongoDB


Create Cloud MongoDB Account
Open cloud.dashboard.com
Left sidebar -> Select Security -> Database Access
Select Add New User button
Enter user name and password and click Add User
Left sidebar > Select Security > Network Access
Select Add IP Address
Enter 0.0.0.0/0 in Whitelist Entry and click Confirm
Left sidebar > Cluster > collections
Create new database, set database name and collection name
Get connection string
Left sidebar > Select Altas > Cluster
Click Connect
Click Connect to your application
Click Copy button
Paste it in your text editor
Replace  and  with step 5, and  with step 10
Use it connection string to publish on heroku (step 6)

ReferenceError: regeneratorRuntime is not defined!

Follow Heroku deploy steps to fix this error.
ERR! build: rmdir /s /q dist && babel backend -d dist

Change your command in package.json to
"scripts": {
 "build": "rm -rf dist && babel backend -d dist",
 ...

How to run project locally

If it does not work you can simply clone the course repo:
https://github.com/basir/node-react-ecommerce
Then follow this guide to run it locally:
https://github.com/basir/node-react-ecommerce#run-locally
Then compare your code with this.
Subtotal ( NaN items) : NaN


clean your cookie
cast selected value in select box for QTY to number. use this:
Number(e.traget.value)
Test it again

PORT IN USE 5000

to fix this issue you need to close all instances of nodejs in process manager in your os. then restart VS Code and it should be fixed.
MongooseServerSelectionError: connect ECONNREFUSED 127.0.0.1:27017

You didn't install and run MongoDB correctly. Install it from https://docs.mongodb.com/manual/administration/install-community/