// MyInput.js
import { withFormsy } from 'formsy-react';
import React from 'react';

class MyInput extends React.Component {
  constructor(props) {
    super(props);
    this.changeValue = this.changeValue.bind(this);
  }

  changeValue(event) {
    // setValue() will set the value of the component, which in
    // turn will validate it and the rest of the form
    // Important: Don't skip this step. This pattern is required
    // for Formsy to work.
    this.props.setValue(event.currentTarget.value);
  }

  render() {
    // An error message is returned only if the component is invalid
    const errorMessage = this.props.getErrorMessage();

    return (
      <div>
        <input
          onChange={this.changeValue}
          type="text"
          value={this.props.getValue() || ''}
        />
        <span>{errorMessage}</span>
      </div>
    );
  }
}

export default withFormsy(MyInput);

import Formsy from 'formsy-react';
import React from 'react';
import MyInput from './MyInput';

export default class App extends React.Component {
  constructor(props) {
    super(props);
    this.disableButton = this.disableButton.bind(this);
    this.enableButton = this.enableButton.bind(this);
    this.state = { canSubmit: false };
  }

  disableButton() {
    this.setState({ canSubmit: false });
  }

  enableButton() {
    this.setState({ canSubmit: true });
  }

  submit(model) {
    fetch('http://example.com/', {
      method: 'post',
      body: JSON.stringify(model)
    });
  }

  render() {
    return (
      <Formsy onValidSubmit={this.submit} onValid={this.enableButton} onInvalid={this.disableButton}>
        <MyInput
          name="email"
          validations="isEmail"
          validationError="This is not a valid email"
          required
        />
        <button type="submit" disabled={!this.state.canSubmit}>Submit</button>
      </Formsy>
    );
  }
}