Target ES6 for ESM bundle #526
Description
Summary
The ESM bundle still targets ES5, which was released in 2009. As far as I can tell, ESM itself was introduced in 2015, so the bundle should really target ES6.
Lines 21 to 22 in 753e8f9
Use-case
Currently, class "extends" are polyfilled. This means that all of liquid's custom error classes show up as basic Error objects, instead of ParseError etc. The effect is, that it's not easy to use instanceof to check if it's a liquid class.