(React-Native) undefined is not a constructor evaluating 'new FormData()'

Question

for the past 2 days I struggled with this problem and can't figure it out. I don't understand this error. this is my code:

try{
var formData = new FormData();
} catch (error) {
console.error('FormData ERROR', error);
}

and this is the error:

017-06-21 13:49:02.761 [error][tid:com.facebook.React.JavaScript] 'FormData ERROR', { [TypeError: undefined is not a constructor (evaluating 'new FormData()')] line: 98419, column: 36, sourceURL: 'http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false' }

Do i have to add support for FormData in ReactNative 0.45.0? please help

Answer 1

I got into this problem as well and that's because I have imported them on top. If you have done like what I did:

import { FormData } from 'react';

or

import { FormData } from 'react-native';

Just remove "FormData" from your imports and it will work like magic. FormData doesn't have to be imported for it to be working.

Answer 2

The error says that you are FormData is undefined. Since it is not part of react native, you probably have to download it from npm.

npm install --save form-data

Then import it at the top of your file

import FormData from 'form-data';

Answer 3

if

import { FormData } from 'react-native';

didn't help then you can try to import directly:

import FormData from 'react-native/Libraries/Network/FormData';