This issue helps me track changes needed to roll out hyperHTML V2.

Breaking Changes

• remove hyperHTML.escape (useless since V0)
• remove hyperHTML.adopt (experimental, V1 too unpredictable, viperHTML has changes for it)
• use document.importNode instead of trusting connect/attributeChanged events (Custom Elements life-cycle will be different and CE will be always upgraded)

Refactoring

• use 100% standard ECMAScript 2015 code as ESM
• avoid transpilation bloat/interference/feature detection issues (use a defined set of transpiling rules instead of the whole 2015 preset)
• use ascjs to create CommonJS version of the module
• use asbundle rollup to create index.js and be sure the resulting code doesn't throw in ES5 based engines
• use uglify-js 2 to create min.js and be sure the resulting code doesn't throw in ES5 based engines
• split dependencies in folders avoiding circular dependencies
• branch out less capable browsers and keep the fast path on modern browsers (too many if/else inside code, just create different callbacks for better/easier code coverage too)
• for custom elements sake, remove hyper HTML attributes before importing and put them back after, avoiding misleading callbacks. Solve all attributes before connecting the node and never after.

Testing / Maintenance

• try to use basicHTML latest version of jsdom to code cover on the server
• make greenkeeper happy if latest jsdom works
• test in isolation each CommonJS file or test index.js all at once. not needed, rollup is better
• aim to the glorious 100% code coverage, trying to avoid ignores for jsdom / nodejs sake

Nice to have

• hyperHTML.adopt(...) based on viperHTML changes and as separate bundle will be out in another release