javascript Arrow Function with One Argumen
let greet = x => console.log(x); greet('Hello'); // Hello
JavaScript arrow functions default parameter
const greeting = (name = "Anonymous") => "Hello " + name; console.log(greeting("John")); console.log(greeting());
Source: www.freecodecamp.org
arrow functions basic usages in 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);
Source: developer.mozilla.org