Dropzone

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The Dropzone allows users to upload files via drag and drop, or by clicking the component. Currently, only one file upload at a time is allowed.

You will also need to provide upload logic yourself via onProcessUpload prop which accepts function that should take care of uploading the file to the backend (i.e. send HTTP request). This function accepts an object with following content as its only argument:

{object} fileData - Metadata about the uploaded file.
{object} requestConfig - Config to pass to axios call (this is required to display progress bar and hande cancel action).
{function} handleError - Function to communicate to Dropzone that file upload resulted in failure, expects Error object as its only argument.

Each example below implements such a function.

Note that Dropzone does not render file after successful upload, you will have to provide that logic yourself depending on which type of file has been uploaded, see this example.

Basic Usage

Drag and drop a file to begin uploading, only one file at a time is allowed, no other validation is done.

Use onUploadProgress prop to get feedback about the upload progress - should be a function that receives (percentageUploaded, progressEvent) as arguments.

Show editable code example

Any Paragon component or export may be added to the code example.

() => {
  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
    />
  )
}

() => {
  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
    />
  )
}

With Progress Bar

Display upload progress as a progress bar with the ability to cancel the upload.

Use onUploadCancel prop to react to upload cancel event - should be a function that takes Response object as its argument.

Show editable code example

Any Paragon component or export may be added to the code example.

() => {
  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadCancel={() => console.log('UPLOAD CANCEL')}
      progressVariant="bar"
    />
  )
}

() => {
  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadCancel={() => console.log('UPLOAD CANCEL')}
      progressVariant="bar"
    />
  )
}

With file size and type validation

Accepts only .png files with size between 1MB and 20MB. The file sizes are specified in bytes. accept prop should be an object with the keys set to the MIME type and the values to an array of file extensions.

For example:

to allow only PNG images (as in this example) you should pass { 'image/*': ['.png'] } object as accept prop;
to allow both PNG and JPG images you should pass { 'image/*': ['.png', '.jpg'] } object as accept prop;
to allow arbitrary images you should pass { 'image/*': [] } object as accept prop

The component will render a helpful message about size and type restrictions based on the values you pass to accept, minSize and maxSize props.

Show editable code example

Any Paragon component or export may be added to the code example.

() => {
  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
      onUploadCancel={() => console.log('UPLOAD CANCEL')}
      progressVariant="bar"
      minSize={1048576}
      maxSize={20 * 1048576}
      accept={{
        "image/*": ['.png'],
      }}
    />
  )
}

() => {
  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
      onUploadCancel={() => console.log('UPLOAD CANCEL')}
      progressVariant="bar"
      minSize={1048576}
      maxSize={20 * 1048576}
      accept={{
        "image/*": ['.png'],
      }}
    />
  )
}

With file preview

Shows image after successful upload.

Show editable code example

Any Paragon component or export may be added to the code example.

() => {
  const [uploadedFile, setUploadedFile] = useState(undefined);

  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
      setUploadedFile(response.data.files.file);
    } catch (error) {
      handleError(error);
    }
  };

  if (uploadedFile) {
    return <Image src={uploadedFile} fluid alt="Image description" />;
  }

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
      onUploadCancel={() => console.log('UPLOAD CANCEL')}
      progressVariant="bar"
      accept={{
        "image/*": [],
      }}
    />
  )
}

() => {
  const [uploadedFile, setUploadedFile] = useState(undefined);

  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
      setUploadedFile(response.data.files.file);
    } catch (error) {
      handleError(error);
    }
  };

  if (uploadedFile) {
    return <Image src={uploadedFile} fluid alt="Image description" />;
  }

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
      onUploadCancel={() => console.log('UPLOAD CANCEL')}
      progressVariant="bar"
      accept={{
        "image/*": [],
      }}
    />
  )
}

With custom error messages

Accepts only .png files with size between 1MB and 20MB, renders custom validation error messages.

Show editable code example

Any Paragon component or export may be added to the code example.

() => {
  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
      onUploadCancel={() => console.log('UPLOAD CANCEL')}
      errorMessages={{
        invalidType: 'Invalid file type, only images allowed.',
        invalidSize: 'The file size must be between 1MB and 20MB.',
        multipleDragged: 'Cannot upload more than one file.',
      }}
      progressVariant="bar"
      minSize={1048576}
      maxSize={20 * 1048576}
      accept={{
        "image/*": ['.png'],
      }}
    />
  )
}

() => {
  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
      onUploadCancel={() => console.log('UPLOAD CANCEL')}
      errorMessages={{
        invalidType: 'Invalid file type, only images allowed.',
        invalidSize: 'The file size must be between 1MB and 20MB.',
        multipleDragged: 'Cannot upload more than one file.',
      }}
      progressVariant="bar"
      minSize={1048576}
      maxSize={20 * 1048576}
      accept={{
        "image/*": ['.png'],
      }}
    />
  )
}

With custom look

Use inputComponent prop to override default view of Dropzone.

Show editable code example

Any Paragon component or export may be added to the code example.

() => {
  const MyInputComponent = <p>Hey! You can render here anything you want ;)</p>;

  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
      inputComponent={MyInputComponent}
    />
  )
}

() => {
  const MyInputComponent = <p>Hey! You can render here anything you want ;)</p>;

  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
      inputComponent={MyInputComponent}
    />
  )
}

With custom validation

You can pass your own validator function which accepts File object as its only argument, the function is invoked after all other validation steps are done. The function should return error message to display in case validation fails, otherwise return null.

Note that Dropzone does not handle unexpected errors that might happen in your function, they should be handled by the validator itself as in the example below.

This example validates that only 400x479 images can be uploaded.

Show editable code example

Any Paragon component or export may be added to the code example.

() => {
  // note that we do not need to validate that received file is actually an image
  // because 'accept' parameter handles that before validation function is used
  async function imageDimensionValidator(file) {
    const image = new window.Image();
    try {
      const url = URL.createObjectURL(file);
      image.src = url;
      await image.decode();
      if (image.width !== 400 || image.height !== 479) {
        return 'The image must have 400x479 dimensions.';
      }
    } catch (error) {
      return 'Unexpected error happened during file validation, please try again.'
    }
    return null;
  }

  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
      onUploadCancel={() => console.log('UPLOAD CANCEL')}
      progressVariant="bar"
      accept={{
        "image/*": []
      }}
      validator={imageDimensionValidator}
    />
  );
}

() => {
  // note that we do not need to validate that received file is actually an image
  // because 'accept' parameter handles that before validation function is used
  async function imageDimensionValidator(file) {
    const image = new window.Image();
    try {
      const url = URL.createObjectURL(file);
      image.src = url;
      await image.decode();
      if (image.width !== 400 || image.height !== 479) {
        return 'The image must have 400x479 dimensions.';
      }
    } catch (error) {
      return 'Unexpected error happened during file validation, please try again.'
    }
    return null;
  }

  async function handleProcessUpload({
    fileData, requestConfig, handleError
  }) {
    const uploadUrl = 'https://httpbin.org/post';
    try {
      const response = await axios.post(uploadUrl, fileData, requestConfig);
    } catch (error) {
      handleError(error);
    }
  };

  return (
    <Dropzone
      onProcessUpload={handleProcessUpload}
      onUploadProgress={(percent) => console.log(percent)}
      onUploadCancel={() => console.log('UPLOAD CANCEL')}
      progressVariant="bar"
      accept={{
        "image/*": []
      }}
      validator={imageDimensionValidator}
    />
  );
}

Reading file contents into memory

Accepts only .xml files up to a size of 20MB. You can read in the contents of the File object into memory. The onProcessUpload prop can retrieve the file Blob from the passed fileData param and either pass it into a file reader or use text() promise.

Note that Dropzone does not handle unexpected errors that might happen in your function, they should be handled by the handleProcessUpload method.

Show editable code example

Any Paragon component or export may be added to the code example.

() => {
  const [text, setText] = useState("");
  const [fileName, setFileName] = useState("");

  const handleProcessUpload = ({ fileData }) => {
    const blob = fileData.get('file');
    blob.text().then(xmlText => {
      setText(xmlText);
      setFileName(blob.name);
    });
  };

  return (
    <>
      <Dropzone
        onProcessUpload={handleProcessUpload}
        onUploadProgress={(percent) => console.log(percent)}
        onUploadCancel={() => console.log('UPLOAD CANCEL')}
        progressVariant="bar"
        maxSize={20 * 1048576}
        accept={{
          "application/xml": ['.xml']
        }}
      />
      {fileName && (
        <Form.Control.Feedback type="valid">
          Uploaded{' '}
          {fileName}
        </Form.Control.Feedback>
      )}
      <p>{text}</p>
    </>
  )
}

() => {
  const [text, setText] = useState("");
  const [fileName, setFileName] = useState("");

  const handleProcessUpload = ({ fileData }) => {
    const blob = fileData.get('file');
    blob.text().then(xmlText => {
      setText(xmlText);
      setFileName(blob.name);
    });
  };

  return (
    <>
      <Dropzone
        onProcessUpload={handleProcessUpload}
        onUploadProgress={(percent) => console.log(percent)}
        onUploadCancel={() => console.log('UPLOAD CANCEL')}
        progressVariant="bar"
        maxSize={20 * 1048576}
        accept={{
          "application/xml": ['.xml']
        }}
      />
      {fileName && (
        <Form.Control.Feedback type="valid">
          Uploaded{' '}
          {fileName}
        </Form.Control.Feedback>
      )}
      <p>{text}</p>
    </>
  )
}

Theme Variables#

CSS Variable	Computed Value
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Props API#

Dropzone Props API

className string
Specifies class name to append to the base element.
accept Object.<string[]>
Set accepted file types. This should be an object with the keys set to the MIME type and the values to an array of file extensions.
maxSize number
Maximum file size (in bytes).
DefaultInfinity
minSize number
Minimum file size (in bytes).
Default0
onUploadProgress func
A callback fired each time an upload progress event happens, receives (percentageUploaded, progressEvent) as arguments.
Default() => {}
onUploadCancel func
A callback fired upon successful upload, receives Response object as a single argument.
Default() => {}
onProcessUpload func Required
A function responsible for uploading the file. Receives following object as its only argument { @param {object} fileData - Metadata about the uploaded file. @param {object} requestConfig - Config to pass to axios call. @param {function} handleError - Function to communicate to Dropzone that file upload resulted in failure, expects Error object to be passed as its only argument. }
errorMessages shape {
invalidType: string | element,
invalidSizeLess: string | element,
invalidSizeMore: string | element,
multipleDragged: string | element,
uploadError: string | element,
}
An object containing error messages, following are supported: 1) invalidType - A message to display when file of invalid type is dropped into Dropzone. Defaults to 'The file type must be {filType} file / one of {fileTypes} files.'. 2) invalidSizeLess - A message to display when file of size less than minSize value is dropped into Dropzone. Defaults to 'File must be larger than {minSize}.'. 3) invalidSizeMore - A message to display when file of size greater than maxSize value is dropped into Dropzone. Defaults to 'File must be less than {maxSize}.'. 4) multipleDragged - A message to display when multiple files are dragged over Dropzone. 5) uploadError - A message to display in case upload results in an error
Default{ invalidType: undefined, invalidSizeLess: undefined, invalidSizeMore: undefined, multipleDragged: undefined, uploadError: undefined, }
progressVariant enum'spinner' | 'bar'
Specifies how the upload progress should be displayed, component shows either spinner or a progress bar.
Default'spinner'
validator func
Custom validation function, receives File object as its only argument. Note that this function will be invoked as a last validation step before beginning an upload process.
inputComponent elementType | node
A component to display initial state of the Dropzone.

Usage Insights#

Dropzone

	Project Name	Paragon Version	Instance Count
	frontend-app-admin-portal	21.13.1	2
	frontend-app-course-authoring	22.8.1	6

Edit this page Leave feedback

Paragon Design System

Theme

Dropzone

Basic Usage

With Progress Bar

With file size and type validation

With file preview

With custom error messages

With custom look

With custom validation

Reading file contents into memory

Theme Variables#

Props API#

Usage Insights#

Dropzone

All components (A-Z)

Theme

Dropzone

Basic Usage#

With Progress Bar#

With file size and type validation#

With file preview#

With custom error messages#

With custom look#

With custom validation#

Reading file contents into memory#

Theme Variables#

Props API#

Usage Insights#

Dropzone

All components (A-Z)

Basic Usage

With Progress Bar

With file size and type validation

With file preview

With custom error messages

With custom look

With custom validation

Reading file contents into memory