javascript 66 lines · 10 steps

Multi-step forms with useActionState in Next.js

A single Server Action drives a two-step signup wizard by returning the next step's state on each submit.

Explained by highlit
Next.js Intermediate server-actions form-state progressive-enhancement multi-step-wizard
1'use client';
2 
3import { useActionState } from 'react';
4import { submitSignup } from './actions';
5 
6const initialState = {
7 step: 1,
8 values: { email: '', password: '', fullName: '', company: '' },
9 errors: {},
10 message: null,
11};
12 
13export function SignupForm() {
14 const [state, formAction, isPending] = useActionState(submitSignup, initialState);
15 const { step, values, errors } = state;
16 
17 return (
18 <form action={formAction} className="signup">
19 <input type="hidden" name="step" value={step} />
20 <ol className="progress">
21 <li className={step >= 1 ? 'active' : ''}>Account</li>
22 <li className={step >= 2 ? 'active' : ''}>Profile</li>
23 </ol>
24 
25 {step === 1 ? (
26 <fieldset disabled={isPending}>
27 <label>
28 Email
29 <input name="email" type="email" defaultValue={values.email} required />
30 </label>
31 {errors.email && <p className="error">{errors.email}</p>}
32 <label>
33 Password
34 <input name="password" type="password" defaultValue={values.password} required />
35 </label>
36 {errors.password && <p className="error">{errors.password}</p>}
37 <button type="submit">{isPending ? 'Checking…' : 'Continue'}</button>
38 </fieldset>
39 ) : (
40 <fieldset disabled={isPending}>
41 <input type="hidden" name="email" value={values.email} />
42 <input type="hidden" name="password" value={values.password} />
43 <label>
44 Full name
45 <input name="fullName" defaultValue={values.fullName} required />
46 </label>
47 {errors.fullName && <p className="error">{errors.fullName}</p>}
48 <label>
49 Company
50 <input name="company" defaultValue={values.company} />
51 </label>
52 <div className="actions">
53 <button type="submit" name="intent" value="back" formNoValidate>
54 Back
55 </button>
56 <button type="submit" name="intent" value="finish">
57 {isPending ? 'Creating account…' : 'Create account'}
58 </button>
59 </div>
60 </fieldset>
61 )}
62 
63 {state.message && <p className="notice">{state.message}</p>}
64 </form>
65 );
66}
01 / 01
STEP 01

Walkthrough

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Three takeaways
  1. 1useActionState lets one Server Action own the entire form lifecycle, returning fresh state after each submission.
  2. 2Carrying prior values in hidden fields keeps a multi-step flow working without client-side state management.
  3. 3Deriving disabled and pending labels from isPending gives free loading feedback during the action.

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