React useFileUpload

A React Hook to make uploading files easier. It extracts away a lot of the boilerplate that comes with allowing users to attach and upload files to your web application. The default browser implementation for uploading files is lame, and doesn't allow you to remove attached files manually, or allow the user to select more files without deleting the previously attached ones.

This hook changes that, and allows you to remove, append, and write over files as you choose. You'll want to hide the default browser input, and create your own custom looking form.

Installation

Installation is simple.

npm i react-use-file-upload or yarn add react-use-file-upload

Usage

import React, { useRef } from 'react';
import axios from 'axios';
import useFileUpload from 'react-use-file-upload';

const Upload = () => {
  const {
    files,
    fileNames,
    fileTypes,
    totalSize,
    totalSizeInBytes,
    handleDragDropEvent,
    clearAllFiles,
    createFormData,
    setFiles,
    removeFile,
  } = useFileUpload();

  const inputRef = useRef();

  const handleSubmit = async (e) => {
    e.preventDefault();

    const formData = createFormData();

    try {
      axios.post('https://some-api.com', formData, {
        'content-type': 'multipart/form-data',
      });
    } catch (error) {
      console.error('Failed to submit files.');
    }
  };

  return (
    <div css={CSS}>
      <h1>Upload Files</h1>

      <p>Please use the form to your right to upload any file(s) of your choosing.</p>

      <div className="form-container">
        {/* Display the files to be uploaded */}
        <div css={ListCSS}>
          <ul>
            {fileNames.map((name) => (
              <li key={name}>
                <span>{name}</span>

                <span onClick={() => removeFile(name)}>
                  <i className="fa fa-times" />
                </span>
              </li>
            ))}
          </ul>

          {files.length > 0 && (
            <ul>
              <li>File types found: {fileTypes.join(', ')}</li>
              <li>Total Size: {totalSize}</li>
              <li>Total Bytes: {totalSizeInBytes}</li>

              <li className="clear-all">
                <button onClick={() => clearAllFiles()}>Clear All</button>
              </li>
            </ul>
          )}
        </div>

        {/* Provide a drop zone and an alternative button inside it to upload files. */}
        <div
          css={DropzoneCSS}
          onDragEnter={handleDragDropEvent}
          onDragOver={handleDragDropEvent}
          onDrop={(e) => {
            handleDragDropEvent(e);
            setFiles(e, 'a');
          }}
        >
          <p>Drag and drop files here</p>

          <button onClick={() => inputRef.current.click()}>Or select files to upload</button>

          {/* Hide the crappy looking default HTML input */}
          <input
            ref={inputRef}
            type="file"
            multiple
            style={{ display: 'none' }}
            onChange={(e) => {
              setFiles(e, 'a');
              inputRef.current.value = null;
            }}
          />
        </div>
      </div>

      <div className="submit">
        <button onClick={handleSubmit}>Submit</button>
      </div>
    </div>
  );
};

Here is a photo of the example app above:

API

files

An array of File objects. if you need access to multiple properties of a File at a time, use this array instead of fileNames and fileTypes, which are mainly included in this hook for convenience.

File[]

fileNames

An array containing just the names of the files.

string[]

fileTypes

An array containing just the file types of the files.

string[]

totalSize

A string that will pretty print the total size of the files. For example, 1024KB, 2MB, 4GB etc.

string

totalSizeInBytes

A number that represents the size of all of the files in bytes.

number

clearAllFiles

A function that will remove all files in the files array.

() => void

createFormData

A function that will prepare the files to be sent to an external API by creating a new FormData object, appending the files to it, and then returning the FormData object.

() => FormData

handleDragDropEvent

A function that prevents you from writing boilerplate code, and will call e.preventDefault and e.stopPropagation behind the scenes.

(e) => void

removeFile

A function that accepts a number(index) or string(name of the file) that will be used to remove a specific file from the files array.

(file: number | string) => void

setFiles

A function that accepts the event emitted from the input field or drop zone, and creates an array of File objects. The default mode is set to, w, which means it will write over previous files each time new ones are attached. If you want previously attached files to not be deleted each time a user attaches new files, then you can opt in by calling setFiles like this, setFiles(e, 'a'), where the a stands for append. If you want the default behavior, there is no need to pass a second argument to this function.

(e: Event, mode = 'w') => void