Converting image-file into base64 in express nodejs

You will need to use Multer middleware to handle multipart/form-data.

const express = require('express')
const multer  = require('multer')
const upload = multer({ dest: 'uploads/' })

const app = express()

app.post('/file_upload', upload.single('example'), (req, res, next) => {
  // req.file is the `example` file or whatever you have on the `name` attribute: <input type="file" name="example" />
  // I believe it is a `Buffer` object.
  const encoded = req.file.buffer.toString('base64')
  console.log(encoded)
})

---

2018-10-24: See David's comment below.

2019-06-11: Fixed example based on comments. It is indeed req.file.buffer: https://github.com/expressjs/multer/blob/master/storage/memory.js#L8

As the previous answer wasn't working for me, I'm sharing this other one that worked. I made with the multer library getting the file and then transforming it to base64

const multer  = require('multer')
const upload = multer({});

router.post('/uploadlogo', upload.single('logo'), (req, res, next) => {
    // encoded has the base64 of your file
    const encoded = req.file.buffer.toString('base64');
});