Import in Vue DocumentEditor component

<template>
        <input type="file" ref="fileUpload" v-on:change="onFileUpload" accept=".dotx,.docx,.docm,.dot,.doc,.rtf,.txt,.xml,.sfdt" style="position:fixed; left:-100em" />
        <div>
            <div>
                  <button v-on:click='openFileButtonClickHandler'>Import</button>
            </div>
            <ejs-documenteditor ref="documenteditor" height="370px" style="width: 100%;display:block"></ejs-documenteditor>
        </div>
</template>
<script>
    import Vue from 'vue'
    import { DocumentEditorPlugin } from '@syncfusion/ej2-vue-documenteditor';

    Vue.use(DocumentEditorPlugin);

    export default {
        data: function() {
            return {
            };
        },
        methods: {
            loadFile: function(file: File): void {
                let ajax: XMLHttpRequest = new XMLHttpRequest();
                ajax.open('POST', 'https://localhost:4000/api/documenteditor/Import', true);
                ajax.onreadystatechange = () => {
                    if (ajax.readyState === 4) {
                        if (ajax.status === 200 || ajax.status === 304) {
                            // open SFDT text in document editor
                            this.$refs.documenteditor.open(ajax.responseText);
                        }
                    }
                }
                let formData: FormData = new FormData();
                formData.append('files', file);
                ajax.send(formData);
            },
            openFileButtonClickHandler: function() {
                this.$refs.fileUpload.click();
            },
            onFileUpload: function(e) {
                if (e.target.files[0]) {
                    let file = e.target.files[0];
                    if (file.name.substr(file.name.lastIndexOf('.')) === '.sfdt') {
                        let fileReader: FileReader = new FileReader();
                        fileReader.onload = (e: any) => {
                            let contents: string = e.target.result;
                            this.$refs.documenteditor.open(contents);
                        };
                        fileReader.readAsText(file);
                    }
                }
            }
        }
    }
</script>
<style>
      @import "../../node_modules/@syncfusion/ej2-vue-documenteditor/styles/material.css";
</style>

    [AcceptVerbs("Post")]
    public string Import(Microsoft.AspNetCore.Http.IFormCollection data)
    {
        if (data.Files.Count == 0)
            return null;
        System.IO.Stream stream = new System.IO.MemoryStream();
        Microsoft.AspNetCore.Http.IFormFile file = data.Files[0];
        int index = file.FileName.LastIndexOf('.');
        string type = index > -1 && index < file.FileName.Length - 1 ?
            file.FileName.Substring(index) : ".docx";
        file.CopyTo(stream);
        stream.Position = 0;

        Syncfusion.EJ2.DocumentEditor.WordDocument document = Syncfusion.EJ2.DocumentEditor.WordDocument.Load(stream, GetFormatType(type.ToLower()));
        string sfdt = Newtonsoft.Json.JsonConvert.SerializeObject(document);
        document.Dispose();
        return sdft;
    }

    internal static Syncfusion.EJ2.DocumentEditor.FormatType GetFormatType(string format)
    {
        if (string.IsNullOrEmpty(format))
            throw new System.NotSupportedException("EJ2 DocumentEditor does not support this file format.");
        switch (format.ToLower()) {
            case ".dotx":
            case ".docx":
            case ".docm":
            case ".dotm":
                return Syncfusion.EJ2.DocumentEditor.FormatType.Docx;
            case ".dot":
            case ".doc":
                return Syncfusion.EJ2.DocumentEditor.FormatType.Doc;
            case ".rtf":
                return Syncfusion.EJ2.DocumentEditor.FormatType.Rtf;
            case ".txt":
                return Syncfusion.EJ2.DocumentEditor.FormatType.Txt;
            case ".xml":
                return Syncfusion.EJ2.DocumentEditor.FormatType.WordML;
            default:
                throw new System.NotSupportedException("EJ2 DocumentEditor does not support this file format.");
        }
    }