salix/loopback/server/boot/storage.js

const uuid = require('uuid/v1');
const md5 = require('md5');

module.exports = app => {
    const storageConnector = app.dataSources.storage.connector;

    storageConnector.getFilename = function(file) {
        return `${uuid()}.${storageConnector.getFileExtension(file.name)}`;
    };

    storageConnector.getFileExtension = function(fileName) {
        return fileName.split('.').pop();
    };

    storageConnector.getPathHash = function(id) {
        return md5(id.toString()).substring(0, 3);
    };
};