Use Node packages not bundled into Postman's sandbox.

Clone this repo.

npm i

node index.js

If you want to jump right into it, import this prebuilt collection and create a global variable called require with value uniq,slapdash,pad-left:

Read on for getting this working with your own existing collection..

Add the following script to the Pre-Request Script of your collection:

const reqs = pm.globals.get('require');
const pkgs = pm.globals.get('packages');
const installed = pm.globals.get('installedPackages');

if (pkgs && (reqs === installed)) {
    eval(pkgs)
} else {
    pm.sendRequest({
        url: `localhost:3000?packages=${reqs}`,
        method: 'GET'
    }, (err, res) => {
        if (!err) {
            eval(res.text());
            pm.globals.set('installedPackages', reqs);
            pm.globals.set('packages', res.text());
        }
    });
}

Create a global variable in Postman called require. Provide a comma separated listed of packages you need e.g. uniq,slapdash,pad-left.

require your packages in the usual way from within folder/request scripts!