ch8n

{ "compilerOptions": {
/* Basic Options */
"target": "es2017", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
"module": "commonjs", /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
// "lib": [],                             /* Specify library files to be included in the compilation. */
// "allowJs": true,                       /* Allow javascript files to be compiled. */
// "checkJs": true,                       /* Report errors in .js files. */
// "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
// "declaration": true,                   /* Generates corresponding '.d.ts' file. */
// "declarationMap": true,                /* Generates a sourcemap for each corresponding '.d.ts' file. */

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"scripts": {
"test": "echo \"Error: no test specified\" && exit 1",
"start": "ts-node src/config/server.ts",
"dev": "nodemon -x ts-node src/config/server.ts"
},

ch8n

import express from 'express';
const app = express()
const port : string|number= process.env.PORT || 5000;
app.use("*",(req, res) =>{res.send("<h1>Welcome to your server!</h1>")})
//create a server object:
app.listen(port,() => console.log(`hosting @${port}`));

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git init .
git add .
git commit -m "init/heroku"

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object Mailer {
    @SuppressLint("CheckResult")
    fun sendMail(email: String, subject: String, message: String): Completable {

        return Completable.create { emitter ->

            //configure SMTP server
            val props: Properties = Properties().also {
                it.put("mail.smtp.host", "smtp.gmail.com")
                it.put("mail.smtp.socketFactory.port", "465")

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//class
data class Person(val name:String,val age:Int)

//instantiate
val person = Person("ch8n", 25)

//access
val name = person.name
val age = person.age

ch8n

//class
data class Person(val name:String,val age:Int)

//instantiate
val developer = Person("Ch8n", 25)

//access
val (name,age) = developer

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//Data Class Destructuring
val person = Person(1, "Chetan", 25)
val(id, name, age) = person

//Collections Destructuring

//map
val map: HashMap<Int, Person> = HashMap()
map.put(1, person)

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// Gotcha #1 
data class Items(val one: String, val two: String)

val items= Items("1","2")
val (one, two, three) = items //Destructuring declaration initializer of type Items must have a 'component3()' function

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//example
data class Items(val one: String, val two: String)

val items= Items("1","2")
val (one, two) = items 

//converts to 
val one = items.component1
val one = items.component2