convert excel file to json using node js

1let express = require('express'),
2    app = express(),
3    bodyParser = require('body-parser'),
4    multer = require('multer'),
5    crypto = require('crypto'),
6    xlsxtojson = require('xlsx-to-json'),
7    xlstojson = require("xls-to-json");
8
9let fileExtension = require('file-extension');
10
11    app.use(bodyParser.json());  
12
13    let storage = multer.diskStorage({ //multers disk storage settings
14        destination: function (req, file, cb) {
15            cb(null, './input/')
16        },
17        filename: function (req, file, cb) {
18            crypto.pseudoRandomBytes(16, function (err, raw) {
19                cb(null, raw.toString('hex') + Date.now() + '.' + fileExtension(file.mimetype));
20                });
21        }
22    });
23
24    let upload = multer({storage: storage}).single('file');
25
26    /** Method to handle the form submit */
27    app.post('/sendFile', function(req, res) {
28        let excel2json;
29        upload(req,res,function(err){
30            if(err){
31                 res.json({error_code:401,err_desc:err});
32                 return;
33            }
34            if(!req.file){
35                res.json({error_code:404,err_desc:"File not found!"});
36                return;
37            }
38
39            if(req.file.originalname.split('.')[req.file.originalname.split('.').length-1] === 'xlsx'){
40                excel2json = xlsxtojson;
41            } else {
42                excel2json = xlstojson;
43            }
44
45           //  code to convert excel data to json  format
46            excel2json({
47                input: req.file.path,  
48                output: "output/"+Date.now()+".json", // output json 
49                lowerCaseHeaders:true
50            }, function(err, result) {
51                if(err) {
52                  res.json(err);
53                } else {
54                  res.json(result);
55                }
56            });
57
58        })
59
60    });
61    // load index file to upload file on http://localhost:3000/
62    app.get('/',function(req,res){
63        res.sendFile(__dirname + "/index.html");
64    });
65
66    app.listen('3000', function(){
67        console.log('Server running on port 3000');
68    });
69