How do i import a script into javascript?

script1.js

export default function Hello() {
return "Hello buddy!";
}

script2.js

import { Hello } from './script1.js';
let val = Hello;
console.log(val);

Run the above sample code blocks in your local system/local server, you will get the console output as: Hello buddy!

Code and Syntax Explanation of the code above:

In script1.js, we exported the module with the syntax of : export module

Similarly, in our case, we exported the function Hello by writing the export keyword in the function definition (line number 1 in script1.js). In script2.js, we imported that module by writing the following code/syntax :

import { Hello } from './script1.js';

Right now in script1.js, we have only one module to export but what if we had multiple modules to export? That is also possible with a similar syntax but with a slight modification:

Sample Code for multiple modules:

script1.js

export let Name = (name) => {return "My name is " + name;}
export let Address = (address) => {return "i live in " + address;}
export let Age = (age) => {return "my age is "+ age;}

script2.js

import { Name, Address, Age} from './script1.js';
let val = Name("John");
let age = Age(26);
console.log(val + " and " + age);

In script1.js, we have three modules named Name, Address, and Age. In Script2.js, we imported those modules with similar but little different syntax.

import { Name, Address, Age} from './script1.js';

Note: we didn’t have { } in earlier import code because that was default export ( remember one file can have only one default export).

When we remove that default keyword in previous code of script1.js, we get an error in the console and that error looks like this:

Infact there are two types of exports:

1. Named Exports (Zero or more exports per module)
2. Default Exports (One per module)

This is only a quick explanation, you can fond more examples at MDN web docs:
Import Statement Reference at MDN
Export Statement Reference at MDN