JAVASCRIPT

JavaScript arrow functions default parameter

const greeting = (name = "Anonymous") => "Hello " + name;

console.log(greeting("John"));
console.log(greeting());

arrow function javascript

// Normal Function in JavaScript
function Welcome(){
  console.log("Normal function");
}

// Arrow Function
const Welcome = () => {
  console.log("Normal function");
}

arrow function javascript

///////
//JavaScript Function Declarations
///////

//4th (arrow function)
hello4 = (name) => { return ("Hello " + name); }
    //OR
hello5 = (name) => { return (`Hello new ${name}`) }

//1st (simple function)
function hello1() {
    return "Hello simple function";
}

//2nd (functino expression)
hello2 = function() {
    return "Hello functino expression";
}

// 3rd ( IMMEDIATELY INVOKED FUNCTION EXPRESSIONS (llFE))
hello3 = (function() {
    return "Hello IMMEDIATELY INVOKED FUNCTION EXPRESSIONS (llFE)";
}())

arrow function javascript

// Function in JavaScript
function regular(){
  console.log("regular function");
}
regular(); //regular function

// Arrow Function
const arrow = () => console.log("Arrow function");
arrow(); //Arrow function

javascript arrow function

// Non Arrow (standard way)
let add = function(x,y) {
  return x + y;
}
console.log(add(10,20)); // 30

// Arrow style
let add = (x,y) => x + y;
console.log(add(10,20)); // 30;

// You can still encapsulate
let add = (x, y) => { return x + y; };

Arrow functions in ES6

let func = (a) => {}         // parentheses optional with one parameter
let func = (a, b, c) => {} // parentheses required with multiple parameters

Arrow functions in Javascript

/**
I think that you might be looking for 
the js "arrow function"; I hope that 
this example below helps ;)
**/ 

// usual function
function fartOne(){
    console.log('Pooofff... pof.. ppf.. poof.. p');
}

// arrow function to do the same
const fartTwo = () => console.log('Baaaf... paf.. poof.. poffie.. plop');

// call the functions to test 'em out..
fartOne();
fartTwo();

how to write an arrow function in javascript?

function double(x) { return x * 2; } // Traditional way
console.log(double(2)) // 4


const double = x => x * 2; // Same function written as an arrow function with implicit return
console.log(double(2)) // 4

js arrow function

// const add = function(x,y) {
//     return x + y;
// }

// const add = (x, y) => {
//     return x + y;
// }

const add = (a, b) => a + b;


const square = num => {
    return num * num;
}

// const rollDie = () => {
//     return Math.floor(Math.random() * 6) + 1
// }

const rollDie = () => (
    Math.floor(Math.random() * 6) + 1
)

javascript Arrow Function with One Argumen

let greet = x => console.log(x);
greet('Hello'); // Hello

arrow function javascript

([a, b] = [10, 20]) => a + b;  // result is 30
({ a, b } = { a: 10, b: 20 }) => a + b; // result is 30

arrow function javascript

const suma = (num1, num2) => num1+num2
console.log(suma(2,3));
//5

javascript arrow function

const welcome = () => {
	console.log("THIS IS A ARROW FUNCTION")
}

arrow function javascript

// Traditional Function
function (a, b){
  return a + b + 100;
}

// Arrow Function
(a, b) => a + b + 100;

// Traditional Function (no arguments)
let a = 4;
let b = 2;
function (){
  return a + b + 100;
}

// Arrow Function (no arguments)
let a = 4;
let b = 2;
() => a + b + 100;

arrow function javascript

// Traditional Function
function (a, b){
  let chuck = 42;
  return a + b + chuck;
}

// Arrow Function
(a, b) => {
  let chuck = 42;
  return a + b + chuck;
}

arrow function javascript

hello = () => {
  return "Hello World!";
}

arrow func in javascript

const greet = (who) => {
  return `Hello, ${who}!`;
};

greet('Eric Cartman'); // => 'Hello, Eric Cartman!'

es6 arrow function

//ES5
var phraseSplitterEs5 = function phraseSplitter(phrase) {
  return phrase.split(' ');
};

//ES6
const phraseSplitterEs6 = phrase => phrase.split(" ");

console.log(phraseSplitterEs6("ES6 Awesomeness"));  // ["ES6", "Awesomeness"]

es6 arrow function

const multiplyES6 = (x, y) => x * y;

Javascript basic arrow function

const power = (base, exponent) => {
    let result = 1;
    for (let count = 0; count < exponent; count++) {
      result *= base;
    }
    return result;
  };

arrow function javascript

// an arrow function is also called a lambda or an anonymous function

let myFunction = () => {
  // some logic
}

arrow functions javascript

// Traditional Function Expression
var add = function(a,b){
  return a + b;
}

// Arrow Function Expression
var arrowAdd = (a,b) => a + b;

arrow function javascript

//arrow function
()=>{}
//normal function
function(){}
//useses of arrow function
var fnct=()=>{}
var fnct=(param1,param2,...rest)=>{console.log(param1),alert(param2),return(rest)}
//or these
var fnct=e=>{}
var fnct=(e)=>e
var fnct=e=>e
//examples
var fnct=param=>{return 'hello '+param}
var fnct=(param1,param2,...rest)=>!param1?param2:rest
var fnct=return_=>return_
var fnct=hi=>alert(hi)

Arrow function in ES6

var array = [1, 2, 3, 4]

const sum = (acc, value) => acc + value
const product = (acc, value) => acc * value

var sumOfArrayElements = array.reduce(sum, 0)
var productOfArrayElements = array.reduce(product, 1)

js arrow function

hello = () => {
	return "Hi All";
}

arrow function javascript

hello4 = (name) => { return ("Hello " + name); }
    //OR
hello5 = (name) => { return (`Hello new ${name}`) }


document.getElementById("arrow").innerHTML = hello4("arrow function");

document.write("<br>" + hello5("arrow function"));

arrow function javascript rules

const add3 = (num1, num2, num3) => return num1 + num2 + num3;

javascript Arrow Function with No Argument

let greet = () => console.log('Hello');
greet(); // Hello

arrow function javascript

const power = (base, exponent) => {
  let result = 1;
  for (let count = 0; count < exponent; count++) {
    result *= base;
  }
  return result;
};

//if the function got only one parameter

const square1 = (x) => { return x * x; };
const square2 = x => x * x;

// empty parameter

const horn = () => {
  console.log("Toot");
};

arrow function javascript

// Traditional Function
function myFunction(param) {
  var a = param * 3;
  return a;
}

//Arrow Function
let myFunction = (a, b) => {
  let c = (a * b) + 3;
  return c;
}

javascript this Inside Arrow Function

const greet = () => {
    console.log(this);
}
greet(); // Window {...}

JavaScript Arrow Function

// function expression
let x = function(x, y) {
   return x * y;
}

arrow function javascript

params => ({foo: "a"}) // returning the object {foo: "a"}

javascript this inside arrow function

function A() {
  this.val = "Error";
  (function() {
    this.val = "Success";
  })();
}

function B() {
  this.val = "Error";
  (() => {
    this.val = "Success";
  })();
}

var a = new A();
var b = new B();
a.val // "Error"
b.val // "Success"

arrow function javascript rules

const square = num => num ** 2;

arrow function javascript rules

const sayHi = ()=>console.log('Hi');

es6 arrow function

// ES6
const prices = smartPhones.map(smartPhone => smartPhone.price);
console.log(prices); // [649, 576, 489]

Arrow Function Shorthand javascript

// Arrow Functions Shorthand javascript
// Longhand:
function sayHello(name) {
  console.log('Hello', name);
}
sayHello("Chetan"); // Hello Chetan

setTimeout(function() {
  console.log('Loaded'); //Loaded
}, 2000);

[1,2,3].forEach(function(item) {
  console.log(item);
// 1
// 2
// 3
});

// Shorthand:
sayHello = name => console.log('Hello', name);
sayHello("Chetan"); //Hello Chetan

setTimeout(() => console.log('Loaded'), 2000); //Loaded

[1,2,3].forEach(item => console.log(item));
// 1
// 2
// 3

javascript Arrow Function Syntax

let myFunction = (arg1, arg2, ...argN) => {
    statement(s)
}

Arrow functions javascript

// Arrow function with two arguments 
const sum = (firstParam, secondParam) => { 
  return firstParam + secondParam; 
}; 
console.log(sum(2,5)); // Prints: 7 
 
// Arrow function with no arguments 
const printHello = () => { 
  console.log('hello'); 
}; 
printHello(); // Prints: hello
 
// Arrow functions with a single argument 
const checkWeight = weight => { 
  console.log(`Baggage weight : ${weight} kilograms.`); 
}; 
checkWeight(25); // Prints: Baggage weight : 25 kilograms.
 
 
// Concise arrow functions
const multiply = (a, b) => a * b; 
console.log(multiply(2, 30)); // Prints: 60

arrow function javascript

const square = num => num * num;

ES6 arrow functions in JavaScript

const greeting = () => console.log('Hello World'); 

arrow function javascript

// An empty arrow function returns undefined
let empty = () => {};

(() => 'foobar')();
// Returns "foobar"
// (this is an Immediately Invoked Function Expression)

var simple = a => a > 15 ? 15 : a;
simple(16); // 15
simple(10); // 10

let max = (a, b) => a > b ? a : b;

// Easy array filtering, mapping, ...

var arr = [5, 6, 13, 0, 1, 18, 23];

var sum = arr.reduce((a, b) => a + b);
// 66

var even = arr.filter(v => v % 2 == 0);
// [6, 0, 18]

var double = arr.map(v => v * 2);
// [10, 12, 26, 0, 2, 36, 46]

// More concise promise chains
promise.then(a => {
  // ...
}).then(b => {
  // ...
});

// Parameterless arrow functions that are visually easier to parse
setTimeout( () => {
  console.log('I happen sooner');
  setTimeout( () => {
    // deeper code
    console.log('I happen later');
  }, 1);
}, 1);

arrow functions javascript

const myFunc = () => "value";

arrow function Java Script

param => expression
(param) => expression

// Arrow Function
(a, b) => {
  const chuck = 42;
  return a + b + chuck;
};