Java Script ES6

//use of var keyword-> variable scope globally

console.log(name);

var name="lalit";

   name="abc";

console.log(name);

name="test";

console.log(name);

//use of let keyword-> variable scope within the block

//console.log(name);

let name="lalit";

   name="abc";

console.log(name);

name="test";

console.log(name);

//use of const keyword-> variable can not possible reassign

//console.log(name);

const name="lalit";

console.log(name);

name="test";

console.log(name);

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//Function Declaration ES5

function greet(name) {

  return "Hello" + " " + name;

}

console.log(greet("lalit"));

//Function Declaration ES6 (Arrow Function)

const greet= (name) => {

  return "Hello There" + " " + name;

};

console.log(greet("Lalit"));

or

const greet= name => { //put code here };

//Function Declaration Multiple Parameter ES6 (Arrow Function)

const greet= (name,age) => {

  return "Hello There" + " " + name + " " + age;

};

console.log(greet("Lalit",30));

//Function Declaration Single Parameter ES6 (Arrow Function)

const Sqr = num => {

  return num*num;

};

console.log(Sqr(6));

or write this

const Sqr = num => num*num;

console.log(Sqr(6));

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//this Keyword  with Arrow Function

//ES5

const person = {

  test(){

  console.log(this);

},

};

person.test();

--------------------------------------------------------------------------

const person = {

  test(){

    var self = this;

    setTimeout( function(){

        console.log(self);

    }, 2000);

},

};

person.test();

ES6

const person = {

  test(){

    //var self = this;

    setTimeout(() => {

        console.log(this);

    }, 2000);

},

};

person.test();

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//Template Literals

-ES5

var name = "lalit";

console.log("welcome to" + " " + name + " ! Have a nice day");

-ES6 -> use tiled symbol and ${varname}

const name1 = "lalit";

console.log(`welcome to ${name1} ! Have a nice day`);

//Print Multiline string in JS

-ES5

//var name = "lalit";

//var res = "Welcome \n to "+name;

//console.log(res);

-ES6

const name = "lalit";

const res = `welcome to Blue 

world mandhana

${name}`;

console.log(res);

*************************************************

Objects Destructing in

-ES5

var details = {

     name: "lalit",

     contact: "1238899",

     email: "abc@gmail.com"

   }

var name = details.name;

var contact = details.contact;

var email = details.email;

console.log(name);

console.log(contact);

console.log(email);

-ES6

let detailsNew = {

     name1: "lalit",

     contact1: "1238899",

     email1: "abc@gmail.com"

   }

const {name1:company_name,contact1,email1} = detailsNew;

console.log(company_name);

console.log(contact);

console.log(email);

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//Array Destructing in

-ES5

var arr = ["A1","A2","A3","A4"]

var v1 = arr[0];

var v2 = arr[1];

var v3 = arr[2];

var v4 = arr[3];

console.log(v1);

console.log(v2);

console.log(v3);

console.log(v4);

-ES6

var arres6 = ["B1","B2","B3","B4"];

let [var1,var2,var3,var4] = arres6;

console.log(var1);

console.log(var2);

console.log(var3);

console.log(var4);

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Spread Operator

//const oldArray = [1,2,3,4,5];

//const newArray = ["A","B","C",...oldArray,6,7,8,9,10];

//console.log(newArray);

Rest Operator  with limited same as parameter value

const sum = (a,b,c,d) => a+b+c+d;

console.log(sum(1,2,3,4));

//console.log(sum(1,2,3,4,5,6,7)); not handle more than parameter(4) value

Rest operator with infinite value

const sum = (...numbers) => {

  let total = 0;

  numbers.forEach((n) => {

    total += n;    

  });

  console.log(total);

}

sum(1,2,3,4,5,6,7,8)

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//Array Map Method

const courses = ["PHP", "ReactJS", "AngularJS", "JavaScript"];

const newCourses = courses.map((c) => {

  return `<li> ${c} </li>`;

});

console.log(courses);

console.log(newCourses);

--------------------------

const series = [1,2,3,4,5,6,7,8,9,10];

const num = 5;

const table = series.map((s) => s*num );

console.log(table);

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