basic Flashcards
package that needs to be added to create a nodejs server
const http = require(‘http’);
how do you create a node server once you have declare the correct package (module)
const server = http.createServer(requestListener)
what is a requestListener?
a function that will be executed for each incoming request. You pass it as a parameter to method server.createServer()
what is the structure of this requestListener?
a two parameter arrow function : (req, res) => { }
how does the server work after you set the requestListener function?
it does nothing unless you run server.listen(). This listen method starts a process in which nodes listen to the requests on the port you specified. Example used is server.listen(3000) that will listen on port 3000
what is the core definition of nodejs? what is it fundamentally. some equivalents in other platforms
a runtime. best homologo is aspnet. but any runtime framework (not only web) is
from the terminal point of view what does nodejs keeps doing while it has listeners registered?
he keeps its event loop to listen for requests. this is the core of nodejs. when there’s no listeners registered then there’s no need to be runing and node ends. in terminal you see it the cursor back ready fr you to open word.
main 3 properties of the req object
req.url, req.method, req.headers
famous header that web pages all have? what is its value?
Content-Type that usually is “text/html”
2 most used method in the response object
res.setHeader, res.write
how do we tell the runtime (node) that we are done writing the response?
res.end();
how do you return 200 or 302 or 500
res.statusCode = 302
what 302 means
status code for redirection
how do you write in a file
fs.writeTextSync(‘filename.txt’, “mnmnmn”);
how do you redirect
res.setHeader(‘Location’, ‘/’); res.statusCode = 302
how do you create the package.json
npm init and filling the information.
what is the name of the field in the package json where you add the autorun configuration? y dentro de este? y then how you specify the app to run?
“scripts” y dentro de este “start”: “node app.js”
how do you run your code from the autorun configuration?
npm start
install nodemon in prod
npm install nodemon –save
install nodemon in dev
npm install nodemon –save-dev
install nodemon globally
npm install nodemon -g
what is the name of folder created by nodejs when you add nodemon
node_modules
when you install nodemon what is added to package. json? y si fuera installed solo para production?
“dev-dependencies”: {
“nodemod”: “^1.2.3”
}
“dependencies” : {
how to make a modules update?
npm install
what does package-lock.json do?
contains references to all the exact versions your project is using. When you publish your project then they can use this to run it against these package and not the latest versions
convenience of deleting the node_package folder. who can readd it again and why?
if you finish working with a package you delete the node_module folder to save space, then since it is declared in the package.json file just running npm install it would get the latest versions again.
what are core nodejs modules ?
you don’t have to install them. just require them. Examples would be the file-system module (“fs”), the path module (“path”) or the Http module (“http”)
what are third party modules?
You need to install them, and require them. nstalled via npm install - you can add any kind of feature to your app via this way Example nodemon
what is a global feature?
features like const or function.
what do you need to change in package.json to allow nodemon work?
not “start”: “node app.js” anymore, but “start”: “nodemon app.js”
why you don’t need to share your modules when you share your application?
because the other developer can run npm install and this will take from package.json and reinstall the latest versions. That way, you don’t need to share node_modules folder.
what are block variables in the debugger?
variables in the caller of the function that is being evaluated. they are blocked waiting
what is the advantage of adding a variable to the watch section in debugger
you can see it while also can close local or other sections
how do you add a configuration file for debugging? what is its name? under what folder is created? what fields need to be added?
debug/Add Configuration. se llama launch.json. .vscode folder. “restart”:true; “runtimeExecutable”: “nodemon” and “console”: “integratedTerminal”
does the debugger configured to re-start, and with nodemon find the package in the local node_modules?
no, you need to install it globally
how do you export a function in nodejs?
module.exports = functionName
ES6 way to declare a function in Javascript?
const functA = (req, res) => {};
conventional folder name for your htmls? and for your routes files?
views and routes
turn arrow function (req, res) => {} into an anonymous function
function(req, res) {}
