When Node.js or a browser imports top-level modules they usually executes top-level code.
{
"exports": {
"import": "./index.js"
},
"execute": {
"browser": "browser",
"node": "node"
}
}
export function browser() {
console.log("Hello, Browser!")
}
export function node() {
console.log("Hello, Node!")
}
$ node .
Hello, Node!
<script src="." type="module" />
Outputs to console
Hello, Browser!