useFetcher for non-navigation mutations in Remix

Introduction

useFetcher lets you send data to the server without changing the page. It helps update or add data quietly, like sending a form without moving to a new screen.

You want to submit a form but stay on the same page.

You need to update some data on the server without reloading the page.

You want to fetch or send data in the background while the user keeps browsing.

You want to handle button clicks that change data but don't navigate away.

You want to show loading or success messages for small actions without page changes.

Syntax

Remix

const fetcher = useFetcher();

// To submit data:
fetcher.submit(data, { method: 'post', action: '/some-action' });

// To render a form:
<fetcher.Form method="post" action="/some-action">
  {/* form fields */}
</fetcher.Form>

fetcher.submit sends data programmatically without navigation.

fetcher.Form is a special form that uses useFetcher internally.

Examples

Sends a POST request with data to '/add-user' without leaving the page.

Remix

const fetcher = useFetcher();

fetcher.submit({ name: 'Alice' }, { method: 'post', action: '/add-user' });

A form that submits data to '/update-profile' but stays on the same page.

Remix

<fetcher.Form method="post" action="/update-profile">
  <input name="email" type="email" />
  <button type="submit">Save</button>
</fetcher.Form>

Sample Program

This component shows a Like button. When clicked, it sends a POST request to '/like' without leaving the page. The button disables while sending and shows 'Liking...'. After success, it shows a confirmation message.

Remix

import { useFetcher } from '@remix-run/react';

export default function LikeButton() {
  const fetcher = useFetcher();

  return (
    <fetcher.Form method="post" action="/like">
      <button type="submit" disabled={fetcher.state === 'submitting'} aria-label="Like button">
        {fetcher.state === 'submitting' ? 'Liking...' : 'Like'}
      </button>
      {fetcher.data?.success && <p role="status">Liked!</p>}
    </fetcher.Form>
  );
}

Important Notes

useFetcher does not cause page reloads or navigation.

Check fetcher.state to show loading or idle states.

Use fetcher.data to access server response after submission.

Summary

useFetcher helps send data quietly without changing pages.

Use fetcher.submit or fetcher.Form for non-navigation actions.

It improves user experience by avoiding full page reloads.

Practice

1. What is the main purpose of useFetcher in Remix?

easy

A. To navigate between different pages

B. To fetch data only on the server side

C. To reload the entire page after submitting a form

D. To send data without changing the current page

Solution

1. Step 1: Understand useFetcher's role

   useFetcher is designed to send data or make requests without causing a page navigation or reload.

2. Step 2: Compare with navigation behavior

   Unlike normal navigation or form submission, it keeps the user on the same page, improving experience.

3. Final Answer:

   To send data without changing the current page -> Option D

4. Quick Check:

   useFetcher = send data quietly [OK]

Hint: useFetcher sends data quietly without page reload [OK]

Common Mistakes:

• Thinking useFetcher causes page navigation
• Confusing useFetcher with normal fetch API
• Assuming useFetcher reloads the page

2. Which of the following is the correct way to submit a form using useFetcher without navigation?

easy

A. fetcher.reload()

B. fetcher.navigate('/submit')

C. fetcher.submit(formData, { method: 'post' })

D. fetcher.fetch('/submit')

Solution

1. Step 1: Identify correct method for non-navigation submission

   fetcher.submit is the method designed to submit data without causing navigation.

2. Step 2: Eliminate incorrect options

   fetcher.navigate causes navigation, fetcher.reload reloads page, and fetcher.fetch is not a valid method.

3. Final Answer:

   fetcher.submit(formData, { method: 'post' }) -> Option C

4. Quick Check:

   submit = fetcher.submit [OK]

Hint: Use fetcher.submit to send form data quietly [OK]

Common Mistakes:

• Using fetcher.navigate which triggers page change
• Trying to reload page instead of submitting
• Using non-existent fetcher.fetch method

3. Given the code snippet below, what will be the behavior when the button is clicked?

const fetcher = useFetcher();

return (
  <fetcher.Form method="post" action="/api/update">
    <input name="name" />
    <button type="submit">Update</button>
  </fetcher.Form>
);

medium

A. The form submits data to /api/update without page reload

B. The page navigates to /api/update after submission

C. The form submission causes a full page reload

D. The form does not submit because fetcher.Form is invalid

Solution

1. Step 1: Understand fetcher.Form behavior

   fetcher.Form submits data without causing navigation or reload, keeping user on the same page.

2. Step 2: Analyze the code snippet

   The form uses method post and action /api/update, so data is sent there quietly on submit.

3. Final Answer:

   The form submits data to /api/update without page reload -> Option A

4. Quick Check:

   fetcher.Form submits quietly = no reload [OK]

Hint: fetcher.Form submits without navigation or reload [OK]

Common Mistakes:

• Assuming fetcher.Form causes navigation
• Thinking it reloads the page
• Believing fetcher.Form is invalid syntax

4. Identify the error in the following code using useFetcher for a non-navigation mutation:

const fetcher = useFetcher();

function handleClick() {
  fetcher.submit({ name: 'Alice' });
}

return <button onClick={handleClick}>Send</button>;

medium

A. fetcher.submit requires a second argument with method and action

B. fetcher.submit cannot be called inside event handlers

C. The button must be inside fetcher.Form to work

D. useFetcher must be called inside handleClick

Solution

1. Step 1: Check fetcher.submit usage

   fetcher.submit needs two arguments: data and an options object specifying method and action.

2. Step 2: Identify missing options

   The code only passes data, missing method and action, so submission will fail or error.

3. Final Answer:

   fetcher.submit requires a second argument with method and action -> Option A

4. Quick Check:

   submit needs data + options [OK]

Hint: Always provide method and action in fetcher.submit options [OK]

Common Mistakes:

• Omitting method and action in submit
• Thinking fetcher.submit works without options
• Calling useFetcher inside event handler

5. You want to update user settings without navigating away or reloading the page. Which approach correctly uses useFetcher to submit the form and handle the response to show a success message?

hard

A. Wrap form in <fetcher.Form> but do not check fetcher.state or fetcher.data

B. Use const fetcher = useFetcher(); then fetcher.submit(formData, { method: 'post', action: '/settings' }) and check fetcher.data to show success

C. Use fetch('/settings', { method: 'post', body: formData }) and reload page on success

D. Use useFetcher but call fetcher.navigate('/settings') after submit

Solution

1. Step 1: Use fetcher.submit with method and action

   Calling fetcher.submit with form data and specifying method and action sends data without navigation.

2. Step 2: Use fetcher.data to detect response and show success

   Checking fetcher.data lets you react to server response and display a success message without reload.

3. Final Answer:

   Use const fetcher = useFetcher(); then fetcher.submit(formData, { method: 'post', action: '/settings' }) and check fetcher.data to show success -> Option B

4. Quick Check:

   submit + check fetcher.data = success message [OK]

Hint: Submit with fetcher.submit and watch fetcher.data for response [OK]

Common Mistakes:

• Reloading page after fetch instead of using fetcher
• Ignoring fetcher.data for response handling
• Using fetcher.navigate which causes navigation