CODE EXAMPLE FOR JAVASCRIPT

storing an image file into buffer field with mongoose

// file-controller.js

const express = require('express');
const mongoose = require('mongoose');
const multer = require('multer');

const router = express.Router();

const multerStorage = multer.memoryStorage();
const upload = multer({ storage: multerStorage, });

const imageSchema = mongoose.Schema({
    image: { data: Buffer, contentType: String },
}, { timestamps: true });

const ImageModel = mongoose.model('images', imageSchema);

router.post('/upload', upload.single('image'), async (req, res, next) => {
    const image = { data: new Buffer.from(req.file.buffer, 'base64'), contentType: req.file.mimetype }
    const savedImage = await ImageModel.create(image);
    res.send(savedImage);
});

router.get('/getImage/:id', async (req, res, next) => {
    const { id: _id } = req.params;
    // If you dont use lean(), you wont decode image as base64
    const image = await ImageModel.findOne({ _id }).lean().exec();
    res.send(image);
});

module.exports = router;