Pass object value in form data to API?

Question

Here is the result of my backend API from POSTMAN:

I got two key here, which is jsonand also itemFile

   createItem(){

     const itemData = this.state;
     const selectedFile = this.state;

     const formData = new FormData();
        formData.append('json', itemData)
        formData.append('itemFile', selectedFile)

        console.log(formData)


        fetch(`http://localhost:9000/api/item/submit`, 
         {
             method: 'post',
             body: formData
         }).then ((result) => {  
                 let responseJSON = result;
                 console.log(responseJSON);
                 });
      }

After that, I got the error of Unrecognized token 'object': was expecting ('true', 'false' or 'null')\n at [Source: (String)\"[object Object]\"; line: 1, column: 8]

Is it I need to use JSON.Stringify? but how would I use it in form-data?

lry · Accepted Answer · 2020-03-12 09:27:12Z

1

itemData in your code must be an object.

FormData append method's second argument should be a USVString or Blob (including subclasses such as File).

If none of these are specified the value is converted to a string by calling toString method.

formData.append('json', itemData)

formData.get('json')  // "[object Object]"

So, you need to use JSON.stringify before appended to formData

formData.append('json', JSON.stringify(itemData))

answered Mar 12, 2020 at 9:27

lry

7583 silver badges7 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Pass object value in form data to API?

1 Answer 1

Comments

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Related