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Class Notes - Day 1 .gitignore is the list of files that will be ignored by git

We want node_modules to be ignored because of the large folder size

When we collaborate with other developers, we clone the repository WITHOUT the node_modules installed, and then we run 'npm i' to install the node_modules

Generators like express-generator will create the boilerplate framework code for us, and then we run 'npm i' to download the list of dependencies.

The package.json comes with a "scripts" config, in there you can define small blocks of code that can be easily invoked from the command line with 'npm run '

Note: For the "start" script, you only need to run "npm start" When we run 'npm start' and the command "node ./bin/www" is invoked, the ./bin/www file will run our app.js file code, which will eventually include all of the code we will write for Express.

The 404 status code means that the url/route we requested does not exist or is not congfigured properly in Express

Every request returns a status code that are grouped into blocks

100 status codes are not used anymore 200 status codes mean success 300 status codes mean partial success 400 status codes mean web errors 500 status codes mean server errors In order to get code from one file into another, we need to use the javascript require() statement.

import/export Quick Aside: Require is being phased out in favor of import/export syntax. HOWEVER, when we are working in an Express environment we need to still use require() because of Node limitations. Note: So for Express we need to use require() and module.exports syntax. require() brings in code from the file we specify in the file path module.exports exports code from a file Note: module.exports = router; is sending the router variable from the route file var indexRouter = require('./routes/index'); is bringing the router variable into the current file as the variable indexRouter app.use('/', indexRouter); is importing the routes we define on indexRouter into our server so that they are exposed as routes. The first argument is the base path for this router The second argument is the router variable Important: All the route paths in our indexRouter are going to be appended to the base path Example: In users.js: router.get('/all', function(req, res, next) { res.send('respond with a resource'); }); In app.js: var usersRouter = require('./routes/users'); app.use('/users', usersRouter); The '/all' path for the route we created in users.js is going to be APPENDED to the base path in app.js. I.E. the final path will be "localhost:3000/users/all" Class Notes - Day 2: Sever-side validation is checking the request inputs before the CRUD operation is executed.

Note: Server-side validation is required to be implemented for all fullstack websites/applications Package.json

dependencies are the libraries/node_modules that are REQUIRED for our application to run devDependencies are the libraries/node_modules that are only needed when doing development work Note: If you are running 'npm i' in a project for the first time after cloning the repo, this will install ALL node_modules including devDependencies Nodemon

Nodemon is a developer library that will restart the server automatically when any of the files inside the repo are changed. Note: If there is an error in our server code, nodemon will crash If the error is with the code we wrote, we can update the code and nodemon will restart If the error is in the execution, nodemon will NOT restart module.exports is the list of code to export from a file. There are two ways to do exports:

Named

A named export is when we export an object containing key/value pairs of variables or functions and we want to access specific variables on that object Export: module.exports = { validateUserData, validateAdminData } Import: File 1: var { validateUserData } = require("../validation/users") File 2: var { validateAdminData } = require("../validation/users") Default

A default export is when a single variable is exported from a file Export: module.exports = router; Import: var usersRouter = require('./routes/users');