javascript: flow: handle new errorformat (#1503)
javascript: flow: handle new errorformat (#1503)

Fixes https://github.com/neomake/neomake/issues/1473.
neomake/neomake,nerdrew/neomake,euclio/neomake,euclio/neomake,neomake/neomake,codeinabox/neomake,nerdrew/neomake