Example 1: arrow function javascript
// Normal Function in JavaScript
function Welcome(){
console.log("Normal function");
}
// Arrow Function
const Welcome = () => {
console.log("Normal function");
}
Example 2: 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; };
Example 3: 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
)
Example 4: arrow function javascript
//If body has single statement
let myFunction = (arg1, arg2, ...argN) => expression
//for multiple statement
let myFunction = (arg1, arg2, ...argN) => {
statement(s)
}
//example
let hello = (arg1,arg2) => "Hello " + arg1 + " Welcome To "+ arg2;
console.log(hello("User","Grepper"))
//Start checking js code on chrome inspect option
Example 5: arrow function map js
const exampleArray = ['aa','bbc','ccdd'];
console.log(exampleArray.map(a => a.length));
//Would print out [2,3,4]
Example 6: 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);