arrow function

JavaScript
// Single-lineconst
implicit = (value) => value;

// Multi-lineconst
implicit = (value) => (
  value
);(param1, param2, …, paramN) => { statements } 
(param1, param2, …, paramN) => expression
// equivalent to: => { return expression; }

// Parentheses are optional when there's only one parameter name:
(singleParam) => { statements }
singleParam => { statements }

// The parameter list for a function with no parameters should be written with a pair of parentheses.
() => { statements }
// The usual way of writing function
const magic = function() {
  return new Date();
};

// Arrow function syntax is used to rewrite the function
const magic = () => {
  return new Date();
};
//or
const magic = () => new Date();

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

// Arrow Function Break Down

// 1. Remove the word "function" and place arrow between the argument and opening body bracket
(a) => {
  return a + 100;
}

// 2. Remove the body brackets and word "return" -- the return is implied.
(a) => a + 100;

// 3. Remove the argument parentheses
a => a + 100;// Traditional Function
function bob (a){
  return a + 100;
}

// Arrow Function
let bob = a => a + 100;Arrow Function is another way to write a function.
"classic method":
function x ()
{
	console.log("X")
}
"arrow method":
var x= ()=>
{
	console.log("X")
}
if we need to add paramiter is pritty simple:
var x = (PARAMS) =>
{
	console.log(PARAMS)
}
Have a nice day 
Source

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