Those slides JavaScript + Other Languages are really useful to implement an eventual Eiffel to JavaScript compiler.
Well, actually it should be called transcompiler….
We could just feed the C files made by current Liberty compiler but it seems to me that passing throught C which is a procedural language like C could easily makes things quite beefier as an Eiffel compiler usually translate all the nifty niceries of Eiffel into low-level C code which could be quite cryptic.