freeCodeCamp/curriculum/challenges/english/03-front-end-libraries/react/create-a-controlled-form.english.md

---
id: 5a24c314108439a4d4036179
title: Create a Controlled Form
challengeType: 6
isRequired: false
---

## Description
<section id='description'>
The last challenge showed that React can control the internal state for certain elements like <code>input</code> and <code>textarea</code>, which makes them controlled components. This applies to other form elements as well, including the regular HTML <code>form</code> element.
</section>

## Instructions
<section id='instructions'>
The <code>MyForm</code> component is set up with an empty <code>form</code> with a submit handler. The submit handler will be called when the form is submitted.
We've added a button which submits the form. You can see it has the <code>type</code> set to <code>submit</code> indicating it is the button controlling the form. Add the <code>input</code> element in the <code>form</code> and set its <code>value</code> and <code>onChange()</code> attributes like the last challenge. You should then complete the <code>handleSubmit</code> method so that it sets the component state property <code>submit</code> to the current input value in the local <code>state</code>.
<strong>Note:</strong>&nbsp; You also must call <code>event.preventDefault()</code> in the submit handler, to prevent the default form submit behavior which will refresh the web page.
Finally, create an <code>h1</code> tag after the <code>form</code> which renders the <code>submit</code> value from the component's <code>state</code>. You can then type in the form and click the button (or press enter), and you should see your input rendered to the page.
</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>MyForm</code> should return a <code>div</code> element which contains a <code>form</code> and an <code>h1</code> tag. The form should include an <code>input</code> and a <code>button</code>.
    testString: assert((() => { const mockedComponent = Enzyme.mount(React.createElement(MyForm)); return (mockedComponent.find('div').children().find('form').length === 1 && mockedComponent.find('div').children().find('h1').length === 1 && mockedComponent.find('form').children().find('input').length === 1 && mockedComponent.find('form').children().find('button').length === 1) })(), '<code>MyForm</code> should return a <code>div</code> element which contains a <code>form</code> and an <code>h1</code> tag. The form should include an <code>input</code> and a <code>button</code>.');
  - text: The state of <code>MyForm</code> should initialize with <code>input</code> and <code>submit</code> properties, both set to empty strings.
    testString: assert(Enzyme.mount(React.createElement(MyForm)).state('input') === '' && Enzyme.mount(React.createElement(MyForm)).state('submit') === '', 'The state of <code>MyForm</code> should initialize with <code>input</code> and <code>submit</code> properties, both set to empty strings.');
  - text: Typing in the <code>input</code> element should update the <code>input</code> property of the component&apos;s state.
    testString: 'async () => { const waitForIt = (fn) => new Promise((resolve, reject) => setTimeout(() => resolve(fn()), 250)); const mockedComponent = Enzyme.mount(React.createElement(MyForm)); const _1 = () => { mockedComponent.setState({ input: '''' }); return waitForIt(() => mockedComponent.state(''input''))}; const _2 = () => { mockedComponent.find(''input'').simulate(''change'', { target: { value: ''TestInput'' }}); return waitForIt(() => ({ state: mockedComponent.state(''input''), inputVal: mockedComponent.find(''input'').props().value }))}; const before = await _1(); const after = await _2(); assert(before === '''' && after.state === ''TestInput'' && after.inputVal === ''TestInput'', ''Typing in the <code>input</code> element should update the <code>input</code> property of the component&apos;s state.''); }; '
  - text: Submitting the form should run <code>handleSubmit</code> which should set the <code>submit</code> property in state equal to the current input.
    testString: 'async () => { const waitForIt = (fn) => new Promise((resolve, reject) => setTimeout(() => resolve(fn()), 250)); const mockedComponent = Enzyme.mount(React.createElement(MyForm)); const _1 = () => { mockedComponent.setState({ input: '''' }); mockedComponent.setState({submit: ''''}); mockedComponent.find(''input'').simulate(''change'', {target: {value: ''SubmitInput''}}); return waitForIt(() => mockedComponent.state(''submit''))}; const _2 = () => { mockedComponent.find(''form'').simulate(''submit''); return waitForIt(() => mockedComponent.state(''submit''))}; const before = await _1(); const after = await _2(); assert(before === '''' && after === ''SubmitInput'', ''Submitting the form should run <code>handleSubmit</code> which should set the <code>submit</code> property in state equal to the current input.''); };'
  - text: The <code>h1</code> header should render the value of the <code>submit</code> field from the component&apos;s state.
    testString: 'async () => { const waitForIt = (fn) => new Promise((resolve, reject) => setTimeout(() => resolve(fn()), 250)); const mockedComponent = Enzyme.mount(React.createElement(MyForm)); const _1 = () => { mockedComponent.setState({ input: '''' }); mockedComponent.setState({submit: ''''}); mockedComponent.find(''input'').simulate(''change'', {target: {value: ''TestInput''}}); return waitForIt(() => mockedComponent.find(''h1'').text())}; const _2 = () => { mockedComponent.find(''form'').simulate(''submit''); return waitForIt(() => mockedComponent.find(''h1'').text())}; const before = await _1(); const after = await _2(); assert(before === '''' && after === ''TestInput'', ''The <code>h1</code> header should render the value of the <code>submit</code> field from the component&apos;s state.''); }; '

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='jsx-seed'>

```jsx
class MyForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      input: '',
      submit: ''
    };
    this.handleChange = this.handleChange.bind(this);
    this.handleSubmit = this.handleSubmit.bind(this);
  }
  handleChange(event) {
    this.setState({
      input: event.target.value
    });
  }
  handleSubmit(event) {
    // change code below this line

    // change code above this line
  }
  render() {
    return (
      <div>
        <form onSubmit={this.handleSubmit}>
          { /* change code below this line */ }

          { /* change code above this line */ }
          <button type='submit'>Submit!</button>
        </form>
        { /* change code below this line */ }

        { /* change code above this line */ }
      </div>
    );
  }
};
```

</div>


### After Test
<div id='jsx-teardown'>

```js
ReactDOM.render(<MyForm />, document.getElementById('root'))
```

</div>

</section>

## Solution
<section id='solution'>


```js
class MyForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      input: '',
      submit: ''
    };
    this.handleChange = this.handleChange.bind(this);
    this.handleSubmit = this.handleSubmit.bind(this);
  }
  handleChange(event) {
    this.setState({
      input: event.target.value
    });
  }
  handleSubmit(event) {
    event.preventDefault()
    this.setState({
      submit: this.state.input
    });
  }
  render() {
    return (
      <div>
        <form onSubmit={this.handleSubmit}>
          <input
            value={this.state.input}
            onChange={this.handleChange} />
          <button type='submit'>Submit!</button>
        </form>
        <h1>{this.state.submit}</h1>
      </div>
    );
  }
};
```

</section>