Whole Cheatsheet

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Zoheb Alli Khan 2021-06-04 16:17:37 +05:30
parent 862c113892
commit 2fa3e1b155
1 changed files with 39 additions and 37 deletions

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@ -2,6 +2,8 @@
* API * API
* http://expressjs.com/en/api.html * http://expressjs.com/en/api.html
* ******************************************************************************************* */ * ******************************************************************************************* */
`npm i express --save` or`yarn add -D express``(-D saves it as a dev dependency)`
`yarn add -D @types/express``(Installing for TS)`
const express = require("express"); // Importing the express library. const express = require("express"); // Importing the express library.
const app = express(); // Intializing the imported express application const app = express(); // Intializing the imported express application
@ -13,7 +15,7 @@ const app = express(); // Intializing the imported express application
```Methods```; ```Methods```;
express.json([options]); `express.json([options]);`
options: ` options: `
inflate // to manage the deflated bodies like enabling and disabling inflate // to manage the deflated bodies like enabling and disabling
@ -28,7 +30,7 @@ verify // It is an undefined function which used to verify th
`; `;
express.raw([options]); `express.raw([options]);`
options: ` options: `
inflate // to manage the deflated bodies like enabling and disabling inflate // to manage the deflated bodies like enabling and disabling
@ -40,7 +42,7 @@ type // This is used to determine the type of middleware wi
verify // It is an undefined function which used to verify the middleware parsing. verify // It is an undefined function which used to verify the middleware parsing.
`; `;
express.Router([options]); `express.Router([options]);`
options: ` options: `
caseSensitive //Enables case sensitivity caseSensitive //Enables case sensitivity
@ -50,7 +52,7 @@ mergeParams //if param names of child and parent are conflicted th
strict // Enables Strict routing strict // Enables Strict routing
`; `;
express.static(root, [options]); `express.static(root, [options]);`
options: ` options: `
dotfiles // determines how dotfiles are used dotfiles // determines how dotfiles are used
@ -68,7 +70,7 @@ LastModified // sets the Last-Modified header to the last modified d
setHeaders // Function for setting HTTP headers to serve with the file setHeaders // Function for setting HTTP headers to serve with the file
`; `;
express.text([options]); `express.text([options]);`
options: ` options: `
defaultCharset // Sets the default charset for the text context. defaultCharset // Sets the default charset for the text context.
@ -82,7 +84,7 @@ type // This is used to determine the type of middleware will
verify // It is an undefined function which used to verify the middleware parsing. verify // It is an undefined function which used to verify the middleware parsing.
`; `;
express.urlencoded([options]); `express.urlencoded([options]);`
options: ` options: `
extended // it allows to choose between parsing the URL-encoded data or the qs library extended // it allows to choose between parsing the URL-encoded data or the qs library
@ -103,7 +105,7 @@ Properties```app.local`;
`app.locals.title = "My Cheatsheet"; `app.locals.title = "My Cheatsheet";
console.dir(app.locals.title)`; // Creating objects with local variables console.dir(app.locals.title)`; `// Creating objects with local variables`
app.mountpath` app.mountpath`
@ -113,35 +115,35 @@ admin.get('/', function(req,res){
res.send('Admin Homepage') res.send('Admin Homepage')
}) })
app.use('<admin dir>', admin)`; // Mounting a sub - app app.use('<admin dir>', admin)`; `// Mounting a sub - app`
``Event`` ``Event``
`admin.on('mount', (parent){ `admin.on('mount', (parent){
console.log('Admin Mounted') console.log('Admin Mounted')
})` // Mounting on a parent app })` `// Mounting on a parent app`
``Methods`` ``Methods``
`app.get('/', function(req, res){ `app.get('/', function(req, res){
res.send('GET request to message') res.send('GET request to message')
})` // get requests to the specified path })` `// get requests to the specified path`
`app.post('/', function(req,res){ `app.post('/', function(req,res){
res.send('POST request to a webpage') res.send('POST request to a webpage')
})` })` `// post request to the specified path`
`app.put('/', function(req,res){ `app.put('/', function(req,res){
res.send('PUT request to a webpage') res.send('PUT request to a webpage')
})` })` `// post request to the specified path`
`app.delete('/', function(req,res){ `app.delete('/', function(req,res){
res.send('DELETE request to a webpage') res.send('DELETE request to a webpage')
})` })` `// delete request to the specified path`
`app.all('/', function(req,res,next){ `app.all('/', function(req,res,next){
console.log('Accessing the secret section....') console.log('Accessing the secret section....')
next() next()
})` })` `// Routing all types of HTTP request`
`app.param('user', function(req,res,next){ `app.param('user', function(req,res,next){
User.find(id, function(err, user){ User.find(id, function(err, user){
@ -154,55 +156,55 @@ app.use('<admin dir>', admin)`; // Mounting a sub - app
next(new Error('Failed to load user')) next(new Error('Failed to load user'))
} }
}) })
})` })` `// Adding callback trigger to route parameters`
`app.use(function(req,res,next){ `app.use(function(req,res,next){
res.send('Hey There!') res.send('Hey There!')
})` })` `// To Invoke the middleware layer that you want to add`
```Request``` ```Request```
``Methods`` ``Methods``
`req.get('content-type')` `req.get('content-type')` `// Returns the specified HTTP req header`
`req.accepts('html')` `req.accepts('html')` `// Checks if the specified content types are available or not`
`req.is('json')` `req.is('json')` `// Requests the matching content-type`
`var range = req.range(1000) `var range = req.range(1000)
if (range.type === 'bytes'){ if (range.type === 'bytes'){
range.forEach(function(r){ range.forEach(function(r){
// Your code
}) })
}` }` `// Range header parser`
``Properties`` ``Properties``
`req.param('name')` `req.param('name')` `// Requests the param name when present`
`app.post('/', function (req, res, next) { `app.post('/', function (req, res, next) {
console.log(req.body) console.log(req.body)
res.json(req.body) res.json(req.body)
})` })` `// Data submitted in the request body`
`console.dir(req.cookies.name)` `console.dir(req.cookies.name)` `// Contains cookies sent by the request`
`console.dir(req.query.q)` `console.dir(req.query.q)` `// Query string parameter in the route`
`console.log(req.route) `console.log(req.route)
res.send('GET')` res.send('GET')` `// Outputs all the layer, methods, path`
`console.dir(req.signedCookies.user)` `console.dir(req.signedCookies.user)` `// Logs all the signed cookies sent by the request`
```Response``` ```Response```
``Methods`` ``Methods``
`res.redirect('https://google.com')` `res.redirect('https://google.com')` `// Redirects to the intended page`
`res.send({message: 'Awesome Stuffs'})` `res.send({message: 'Awesome Stuffs'})` `// Response to the webpage`
`res.json({alert: 'awesomecheatsheets'})` `res.json({alert: 'awesomecheatsheets'})` `// Response in JSON type`
`const file = req.params.name; `const file = req.params.name;
res.sendFile(file, options, function(err){ res.sendFile(file, options, function(err){
@ -211,9 +213,9 @@ res.sendFile(file, options, function(err){
}else{ }else{
console.log('Sent:', file) console.log('Sent:', file)
} }
})` })` `// Sends file to the intended path`
`res.render('index')` `res.render('index')` `// Rendering the intended file`
```BodyParser``` ```BodyParser```
@ -221,4 +223,4 @@ res.sendFile(file, options, function(err){
app.use(BodyParser.json()) app.use(BodyParser.json())
app.use(BodyParser.urlencoded({ app.use(BodyParser.urlencoded({
extended: true extended: true
}))` }))` `// Parses incoming request bodies`