I'd imagine someone could build a Chrome extension to do this as a fully client-side solution... i.e. Grab all the scripts on a site, recompile for something li

I'd imagine someone could build a Chrome extension to do this as a fully client-side solution... i.e. Grab all the scripts on a site, recompile for something like an ES5 target, and then replace them with the locally compiled scripts. The issues are probably rare enough though that there is little motivation to actually do this.