[SOLVED] Is there anyway to have a filesystem-like facility on ESP8266?

@allObjects Thank you, here I could achieve the solution:

# create bundle
BUNDLE="init.min.js"
echo "" > ${BUNDLE}

# Register modules via `Modules.addCached()` method
# see: http://forum.espruino.com/comments/12899741/
MODULE_NAME="FlashEEPROM"
MODULE_STR=$(uglifyjs -c -m -- ${MODULE_NAME}.js | sed 's/\"/\\\"/g' | sed "s/\n//g")
echo "Modules.addCached(\"${MODULE_NAME}\", \"${MODULE_STR}\");" >> ${BUNDLE}
uglifyjs -c -m --  init.js >> ${BUNDLE}

Now I can require("FlashEEPROM") as expected.