For Vega, I would use the pre-built minified ES5 version: https://github.com/vega/vega#es5-support https://github.com/vega/vega#es5-support Add a <script src=>

For Vega, I would use the pre-built minified ES5 version: https://github.com/vega/vega#es5-support https://github.com/vega/vega#es5-support Add a <script src=> tag. Access it by object destructuring a global variable. You can access ES5 stuff from ES6, just let ES5 run first.