Cannot set property 'isEditing' of undefined

[Azylak]

Hi,

I get this error now after installing Vuse; Cannot set property 'isEditing' of undefined.

var Vuse = function Vuse (options) {
  this.isEditing = true;
  this.isSorting = false;
  this.isRendered = false;
  this.title = options.title;
  this.intro = options.intro;
  this.sections = options.sections;
  this.columnsPrefix = options.columnsPrefix;
  this.themes = options.themes;
  this.components = {};
  this.assets = {
    css: options.css || 'dist/css/app.css'
  };
  this.installPlugins();
};

I installed Vuse only in the component I need it in. Below my App.vue

<template>
    <div>
        <b-builder @saved="onSave"></b-builder>
    </div>
</template>
<script>
import builder from 'vuse';

export default {
    components: {
        widget,
        'b-builder': builder,
    },
    methods: {
        onSave( vuse ) {
          console.log('on Save');
        },
    }
}
</script>