Getting Started (class)

Install

npm install --save mobx-formkit

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1. Choose a Validation Plugin

MobX Formkit supports multiple validation plugins. Below we use DVR (Declarative Validation Rules) with validatorjs:

import dvr from 'mobx-formkit/lib/validators/DVR';
import validatorjs from 'validatorjs';

See Validation Plugins for all supported validators: VJF (vanilla functions), DVR (declarative rules), AJV (JSON Schema), YUP, JOI, ZOD, VALIBOT, VINEJS.

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2. Define the Form Class

Extend the Form class and use its lifecycle methods to configure plugins, fields, and hooks:

import { Form } from 'mobx-formkit';
import dvr from 'mobx-formkit/lib/validators/DVR';
import validatorjs from 'validatorjs';

class MyForm extends Form {

  // Validation plugins
  plugins() {
    return {
      dvr: dvr({ package: validatorjs }),
    };
  }

  // Fields definition
  setup() {
    return {
      fields: [{
        name: 'email',
        label: 'Email',
        placeholder: 'Insert Email',
        rules: 'required|email|string|between:5,25',
        value: 's.jobs@apple.com',
      }, {
        name: 'password',
        label: 'Password',
        placeholder: 'Insert Password',
        rules: 'required|string|between:5,25',
      }, {
        name: 'passwordConfirm',
        label: 'Password Confirmation',
        placeholder: 'Confirm Password',
        rules: 'required|string|same:password',
      }],
    };
  }

  // Event hooks
  hooks() {
    return {
      onSuccess(form) {
        alert('Form is valid! Send the request here.');
        console.log('Form Values!', form.values());
      },
      onError(form) {
        alert('Form has errors!');
        console.log('All form errors', form.errors());
      },
    };
  }
}

The setup() method replaces the first constructor argument. Similarly, options(), plugins(), bindings(), hooks(), and handlers() can be defined as class methods.

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3. Create the Form

const form = new MyForm();

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4. Use in a React Component

The form provides built-in Event Handlers: onSubmit(e), onClear(e), onReset(e) & more.

import React from 'react';
import { observer } from 'mobx-react';

export default observer(({ form }) => (
  <form>
    <label htmlFor={form.$('email').id}>
      {form.$('email').label}
    </label>
    <input {...form.$('email').bind()} />
    <p>{form.$('email').error}</p>

    {/* ... other fields ... */}

    <button type="submit" onClick={form.onSubmit}>Submit</button>
    <button type="button" onClick={form.onClear}>Clear</button>
    <button type="button" onClick={form.onReset}>Reset</button>

    <p>{form.error}</p>
  </form>
));

All field props are accessible via form.$('fieldName') — see Field Properties.

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What's Next?

Topic	Link
Simple (non-class) form definition	Quick Start
TypeScript usage	TypeScript Guide
Nested & array fields	Defining Fields
Validation plugins deep-dive	Validation
Live demo	foxhound87.github.io/mobx-formkit-demo

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💡 TypeScript — The Form class accepts a generic for type-safe field access:

class MyForm extends Form<{ email: string; password: string }> {
  // ...
}

const form = new MyForm();
form.$('email').value; // typed as string

See the TypeScript Guide for details.