[Vuejs]-Importing services in Vue.js

This code says that you have declared utils as you imported. So that was the declaration part. But what about definition? In definition there is main play happening around for which that declared utils is used in code. So I think it creates warning that it is not defined. You should use it via registering like Vue.use(componentname/pluginname). This all should be done in index.js and then should be used in components

Anyhow hope this clears for you!