Modern Js

One-minute read

Arrow functions

Arrow functions have this syntax:

const myFunction = () => { //… }

The spread operator

If you see

const c = […a]

This statement copies an array.

You can add items to an array as well, using

const c = […a, 2, ‘test’]

The … is called spread operator.

Destructuring assignments

You can extract just some properties from an object using this syntax:

const person = { firstName: ‘Tom’, lastName: ‘Cruise’, actor: true, age: 54 }

const { firstName: name, age } = person

You will now have two const values name and age.

The syntax also works on arrays:

const a = [1,2,3,4,5] [first, second, , , fifth] = a

Template literals

If you see strings enclosed in backticks, it’s a template literal:

const str = test Inside this, you can put variables and execute javascript, using ${…} snippets:

const string = something ${1 + 2 + 3}

const string2 = something ${doSomething() ? 'x' : 'y'}

And also, you can span a string over multiple lines:

const string3 = `Hey this

string is awesome!`