Javascript module

JavaScript Modules (ES6) let you split code into multiple files and reuse code cleanly.

Main keywords:

• export → make something available from a file to outside.

• import → use something from another file into a file.

export:

Use export when you want to share variables, functions, or classes from a file.

math.js

export const pi = 3.14;

export function add(a, b) {
  return a + b;
}
Here, pi and add() can be used in other files.
import:
Use import to bring exported things into another file.
app.js
import { pi, add } from "./math.js";

console.log(pi);        // 3.14
console.log(add(2, 3)); // 5
Default Export
A file can have one default export.
user.js
export default function greet() {
  console.log("Hello");
}
Import it without {}
app.js
import greet from "./user.js";

greet();