See from line 384 @zeljkofilipin
I've asked for advice in https://gerrit.wikimedia.org/r/c/mediawiki/extensions/MobileFrontend/+/698252/1#message-9a5d77e9fb7c9fc3dac9ff371343ec38981ddf4a
node v 10.15.2 npm v 6.14.5