Req.body is not iterable in node.js

All we need is an easy explanation of the problem, so here it is.

I am building mock restful API to learn better. I am using MongoDB and node.js, and for testing I use postman.

I have a router that sends update request router.patch. In my DB, I have name (string), price (number) and imageProduct (string – I hold the path of the image).

I can update my name and price objects using raw-format on the postman, but I cannot update it with form-data. As I understand, in raw-form, I update the data using the array format. Is there a way to do it in form-data? The purpose of using form-data, I want to upload a new image because I can update the path of productImage, but I cannot upload a new image public folder. How can I handle it?

Example of updating data in raw form

[ {"propName": "name"}, {"value": "test"}]


router.patch('/:productId', checkAuth, (req, res, next) => {
const id = req.params.productId;

const updateOps = {};

for (const ops of req.body) {
    updateOps[ops.propName] = ops.value;
Product.updateMany({_id: id}, {$set: updateOps})
    .then(result => {
            message: 'Product Updated',
            request: {
                type: 'GET',
                url: 'http://localhost:3000/products/' + id
    .catch(err => {
            err: err

How to solve :

I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.

Method 1

Using for…of is a great idea, but you can’t use it like you are to loop through an object’s properties. Thankfully, Javascript has a few new functions that turn ‘an object’s properties’ into an iterable.

Using Object.keys:

const input = {
  firstName: 'Evert',
for (const key of Object.keys(input)) {
  console.log(key, input[key]);

You can also use Object.entries to key both the keys and values:

const input = {
  firstName: 'Evert',
for (const [key, value] of Object.entries(input)) {
  console.log(key, value);

Method 2

I know this answer might be too late to help you but it might help someone in 2020 and beyond.

First, comment out this block:

//const updateOps = {};

//for (const ops of req.body) {
//updateOps[ops.propName] = ops.value;

and change this line:

Product.updateMany({_id: id}, {$set: updateOps})

to this:

Product.updateMany({_id: id}, {$set: req.body})

Everything else is fine. I was having similar issues, but this link helped me:
[What is the difference between ( for… in ) and ( for… of ) statements in JavaScript?

Method 3

To handle multi-part form data, the bodyParser.urlencoded() or app.use(bodyParser.json());body parser will not work.

See the suggested modules here for parsing multipart bodies.

You would be required to use multer in that case

 var bodyParser = require('body-parser');
 var multer = require('multer');
 var upload = multer();

// for parsing application/json

// for parsing application/xwww-
app.use(bodyParser.urlencoded({ extended: true })); 

// for parsing multipart/form-data

Note: Use and implement method 1 because this method fully tested our system.
Thank you 🙂

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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