JavaScript ES6 / ES2015 - My Notes

Using ES6 in Prod

• Supported by modern but not by older browsers
• So, ES6 needs to be transpiled or multipiled in prod

The let and const

• const - generates an error when attempted to change value
• both - block-scoped while var was function scoped (a block is just {...})
• Now, instead of using IIFE, we can use a block. Variables (and function expressions assigned to variables) marked const or let will be private. While those marked with var will be public.

Strings

• Template liters (note back-ticks): His name is ${firstName} ${lastName}.

Arrow Functions

• If we have an array arr1, then arr1.map(el => 2 * el) will return an array of doubled numbers.
• In fuller format:

  arr1.map((elem, index) => {
    ....
    return ...
  })

• Arrow functions don't have their own this. They use the this of the function they written in - it's called lexical this.