react-use-file-upload

React useFileUpload

A React Hook to make dealing with files in an upload scenario easier. It extracts away a lot of the boilerplate that comes with allowing users to add their own files to your web application.

Usage

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

const Upload = () => {
  const { files, handleDragDropEvent, clearAllFiles, createFormData, setFiles, fileNames, fileTypes, 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>

      <form onSubmit={handleSubmit}>
        <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 && (
              <div>
                <span>File types found: {fileTypes.join(', ')}</span>

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

        <div className="submit">
          <button type="submit">Submit</button>
        </div>
      </form>
    </div>
  );
};

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