How use openlayers3 in vuejs?

Through npm install openlayers(4.1.1), I can use openlayers normally in vuejs, but our company custom something base openlayers3.x, so how can I user this custom openlayers? I improt this ol's lib directly, when uses

goog.require("ol.Map")

it reports goog undefined error! so, is there any approach to use the custom ol in vuejs? thix.

via fengzhang