test

test.md

import * as say from './say.js';

say.sayHi('John');
say.sayBye('John');

1. Modern build tools (webpack and others) bundle modules together and optimize them to speedup loading and remove unused stuff.

   Let’s say, we added a 3rd-party library say.js to our project with many functions:

   // 📁 say.js
   export function sayHi() { ... }
   export function sayBye() { ... }
   export function becomeSilent() { ... }

   Now if we only use one of say.js functions in our project:

   // 📁 main.js
   import {sayHi} from './say.js';

   …Then the optimizer will see that and remove the other functions from the bundled code, thus making the build smaller. That is called “tree-shaking”.