Handling File Fields using React Hook Form

In this article, we will learn how to handle file uploads using 

 is a great library that provides an easy way to build forms with React. It provides a number of 

 that simplify the process of defining and validating various types of form fields. In the following sections, we will learn how to define a file input, and use it to upload files to 

 to generate a stock React app. We'll call our app 

npx create-react-app react-hook-form-file-input

Once the app is ready, we can navigate into the folder and install 

cd react-hook-form-file-input
yarn add react-hook-form

 file. We can remove all the default markup added by 

 element which contains a file input and a submit button like so:

import React from "react";

function App() {
  return (
    <form>
      <input type="file" name="picture" />
      <button>Submit</button>
    </form>
  );
}

export default App;


 function which, as the name suggests, connects a given element with 

import React from "react";
import { useForm } from "react-hook-form";

function App() {
  const { register } = useForm();

  return (
    <form>
      <input ref={register} type="file" name="picture" />
      <button>Submit</button>
    </form>
  );
}

export default App;


Now that our file input has been registered, we can handle submissions by adding an 

import React from "react";
import { useForm } from "react-hook-form";

function App() {
  const { register, handleSubmit } = useForm();

  const onSubmit = (data) => {
    console.log(data);
  };

  return (
    <form onSubmit={handleSubmit(onSubmit)}>
      <input ref={register} type="file" name="picture" />
      <button>Submit</button>
    </form>
  );
}

export default App;


 is an object whose keys are the names of the fields, and values are the values of the respective fields.

On choosing a file and clicking 'Submit', details about the uploaded file will be logged to the console.

Now that we have learnt how to work with file inputs using 

, let us look at a slightly more advanced use case for uploading files to 

You can find the code for the Firebase file upload example 

git clone https://github.com/satansdeer/firebase-file-upload
yarn

You can set up your Firebase configuration in the 

 files at the root of the project, and log into Firebase using the 

 file contains a file input which uploads a file to Firebase.

import React from 'react';
import './App.css';
import {app} from './base'

function App() {
  const onChange = (e) => {
    const file = e.target.files[0];
    const storageRef = app.storage().ref()
    const fileRef = storageRef.child(file.name)
    fileRef.put(file).then(() => {
      console.log("Uploaded a file")
    })
  }

  return (
    <input type="file" onChange={onChange}/>
  );
}

export default App;


import React from "react";
import "./App.css";
import { app } from "./base";
import { useForm } from "react-hook-form";

function App() {
  const { register, handleSubmit } = useForm();

  const onSubmit = (data) => {
    const file = data.image[0];
    const storageRef = app.storage().ref();
    const fileRef = storageRef.child(file.name);
    fileRef.put(file).then(() => {
      console.log("Uploaded a file");
    });
  };

  return (
    <form onSubmit={handleSubmit(onSubmit)}>
      <input
        ref={register}
        name="image"
        type="file" />
    </form>
  );
}

export default App;


 command and it will look the same as earlier.

Choosing a file and clicking 'Submit' will upload it to Firebase.

We have now learnt how to work with file inputs using 

The code used in this article is available at  

https://github.com/satansdeer/react-hook-form-file-input

https://github.com/satansdeer/firebase-file-upload

AUTHOR

Maksim Ivanov

In this article, we will learn how to handle file uploads using react-hook-form.

Andreea Macoveiciuc

In this article, we'll cover two ways to create React forms: the HTML way, with uncontrolled components, and the best practice, with controlled components.We'll discuss concepts such as: what are controlled and uncontrolled components, main tags used in a React form, and form validation and submission.

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