Tipsy is a plugin for jQuery. "TypeError: $(...).tipsy is not a function" means that there is no function called tipsy on the jQuery object. Try to include the plugin after jQuery and before your script.

If you're using vue-loader and webpack, install tipsy with npm install jtipsy --save and try the following:

import $ from 'jquery'

export default {
  name: 'TreeView',
  mounted () {
    // Your code here