[jeroenhd]

This solution seems a lot cleaner to me syntactically, but it does lack helpers like .concat(). You'd have to write methods like .pipe( x => x + "!") to extend methods. Then again, prefixing and postfixing operaties shouldn't be too hard to write either

[porridgeraisin]

I like

https://github.com/WiseLibs/wise-river

For complex uses