Tutorial by Examples: r

case thing of Cat -> meow Bike -> ride Sandwich -> eat _ -> Debug.crash "Not yet implemented" You can use Debug.crash when you want the program to fail, typically used when you're in the middle of implementing a case ex...

func loginHandler(w http.ResponseWriter, r *http.Request) { // Steps to login } func main() { http.HandleFunc("/login", loginHandler) http.ListenAndServe(":8080", nil) }

// logger middlerware that logs time taken to process each request func Logger(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { startTime := time.Now() h.ServeHttp(w,r) endTime := time.Since(startTime) log...

func CORS(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { origin := r.Header.Get("Origin") w.Header().Set("Access-Control-Allow-Origin", origin) if r.Method == "OPTIONS" { ...

func Authenticate(h http.Handler) http.Handler { return CustomHandlerFunc(func(w *http.ResponseWriter, r *http.Request) { // extract params from req // post params | headers etc if CheckAuth(params) { log.Println("Auth Pass") // pas...

func Recovery(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request){ defer func() { if err := recover(); err != nil { // respondInternalServerError } }() h.ServeHTTP(w , r) }...

16#A8# -- hex 2#100# -- binary 2#1000_1001_1111_0000 -- long number, adding (optional) _ (one or more) for readability 1234 -- decimal

Usually output of a command goes to the terminal. Using the concept of Output redirection, the output of a command can be redirected to a file. So insted of displaying the output to the terminal it can be send to a file. '>' character is used for output redirection. $ pwd > file1 $ cat file...

The commands normally take their input from the standard input device keyboard. Using Input redirection concept, we can have their input redirected from a file. To redirect standard input from a file instead of the keyboard, the '<' character is used. $ cat file1 monday tuesday wednsday th...

type state_t is (START, READING, WRITING); -- user-defined enumerated type

Step 1 : Install the node-inspector package using npm globally on you machine $ npm install -g node-inspector Step 2 : Start the node-inspector server $ node-inspector Step 3 : Start debugging your node application $ node --debug-brk your/short/node/script.js Step 4 : Open http://127.0....

Is raised when you tried to use a variable, method or function that is not initialized (at least not before). In other words, it is raised when a requested local or global name is not found. It's possible that you misspelt the name of the object or forgot to import something. Also maybe it's in anot...

AssertError The assert statement exists in almost every programming language. When you do: assert condition or: assert condition, message It's equivalent to this: if __debug__: if not condition: raise AssertionError(message) Assertions can include an optional message, and you can d...

If all you need is serializing mongo results into json, it is possible to use the json module, provided you define custom handlers to deal with non-serializable fields types. One advantage is that you have full power on how you encode specific fields, like the datetime representation. Here is a ha...

Import a Mongoose Model (See topic "Mongoose Schemas") var User = require("../models/user-schema.js") The findOne method will return the first entry in the database that matches the first parameter. The parameter should be an object where the key is the field to look for and th...

new Vue({ el:"#app", data:{ foo: "bar" }, methods:{ doSomethingAsynchronous(){ setTimeout(function(){ // This is wrong! Inside this function, // "this" refers to the window object. this.foo = "baz"; ...

new Vue({ el:"#star-wars-people", data:{ people: null }, mounted: function(){ $.getJSON("http://swapi.co/api/people/", function(data){ // Again, this is wrong! "this", here, refers to the window. this.people = data.results; }) ...

You can capture the correct this using a closure. new Vue({ el:"#star-wars-people", data:{ people: null }, mounted: function(){ // Before executing the web service call, save this to a local variable var self = this; $.getJSON("http://swapi.co/api/peop...

You can bind the callback function. new Vue({ el:"#star-wars-people", data:{ people: null }, mounted:function(){ $.getJSON("http://swapi.co/api/people/", function(data){ this.people = data.results; }.bind(this)); } })

new Vue({ el:"#star-wars-people", data:{ people: null }, mounted: function(){ $.getJSON("http://swapi.co/api/people/", data => this.people = data.results); } }) Caution! Arrow functions are a syntax introduced in Ecmascript 2015. It is not yet supp...