Rnw-dropzone NPM

react-dropzone

Simple HTML5-compliant drag'n'drop zone for files built with React.js.

Documentation and examples: https://react-dropzone.js.org Source code: https://github.com/react-dropzone/react-dropzone/

Installation

Install it from npm and include it in your React build process (using Webpack, Browserify, etc).

npm install --save react-dropzone

or:

yarn add react-dropzone

Usage

import React from 'react'
import classNames from 'classnames'
import Dropzone from 'react-dropzone'

class MyDropzone extends React.Component {
   onDrop = (acceptedFiles, rejectedFiles) => {
     // Do something with files
   }

   render() {
    return (
      <Dropzone onDrop={this.onDrop}>
        {({getRootProps, getInputProps, isDragActive}) => {
          return (
            <div
              {...getRootProps()}
              className={classNames('dropzone', {'dropzone--isActive': isDragActive})}
            >
              <input {...getInputProps()} />
              {
                isDragActive ?
                  <p>Drop files here...</p> :
                  <p>Try dropping some files here, or click to select files to upload.</p>
              }
            </div>
          )
        }}
      </Dropzone>
    );
  }
}

Render Prop Function

The render property function is what you use to render whatever you want to based on the state of Dropzone:

<Dropzone>
  {({getRootProps}) => <div {...getRootProps()} />}
</Dropzone>

Prop Getters

See https://react-dropzone.netlify.com/#proptypes {children} for more info.

These functions are used to apply props to the elements that you render.

This gives you maximum flexibility to render what, when, and wherever you like. You call these on the element in question (for example: <div {...getRootProps()} />).

You should pass all your props to that function rather than applying them on the element yourself to avoid your props being overridden (or overriding the props returned). E.g.

<div
  {...getRootProps({
    onClick: evt => console.log(event)
  })}
/>

State

See https://react-dropzone.netlify.com/#proptypes {children} for more info.

Custom refKey

Both getRootProps and getInputProps accept custom refKey (defaulted to ref) as one of the attributes passed down in the parameter.

const StyledDropArea = styled.div`
// Some styling here
`
const Example = () => (
  <Dropzone>
   {({ getRootProps, getInputProps }) => (
      <StyledDropArea {...getRootProps({ refKey: 'innerRef' })}>
        <input {...getInputProps()} />
        <p>Drop some files here</p>
      </StyledDropArea>
    )}
  </Dropzone>
);

Warning: On most recent browsers versions, the files given by onDrop won't have properties path or fullPath, see this SO question and this issue. If you want to access file content you have to use the FileReader API.

onDrop: acceptedFiles => {
    acceptedFiles.forEach(file => {
        const reader = new FileReader();
        reader.onload = () => {
            const fileAsBinaryString = reader.result;
            // do whatever you want with the file content
        };
        reader.onabort = () => console.log('file reading was aborted');
        reader.onerror = () => console.log('file reading has failed');

        reader.readAsBinaryString(file);
    });
}

PropTypes

See https://react-dropzone.netlify.com/#proptypes

Testing

Important: react-dropzone makes its drag'n'drop callbacks asynchronous to enable promise based getDataTransfer functions. In order to properly test this, you may want to utilize a helper function to run all promises like this:

const flushPromises = () => new Promise(resolve => setImmediate(resolve));

Example with enzyme 3:

it('tests drag state', async () => {
  const flushPromises = () => new Promise(resolve => setImmediate(resolve));
  const DummyChildComponent = () => null
  const dropzone = mount(
    <Dropzone>{props => <DummyChildComponent {...props} />}</Dropzone>
  )
  dropzone.simulate('dragEnter', {
    dataTransfer: { files: files.concat(images) }
  })
  await flushPromises(dropzone)
  dropzone.update()

  const child = dropzone.find(DummyChildComponent)
  expect(child).toHaveProp('isDragActive', true)
  expect(child).toHaveProp('isDragAccept', false)
  expect(child).toHaveProp('isDragReject', true)
})

Remember to update your mounted component before asserting any props. A complete example for this can be found in react-dropzones own test suite.