Usage

<VerifyField
  value={this.state.username}
  onChange={this.handleChange}
  name='username'
  required
>
  {({ isDirty, isRequired, tail }) => (
    <div>
      <input type='text' { ...tail } />
      {isDirty && !isRequired && <span>Please enter a username</span>}
    </div>
  )}
</VerifyField>

// Or

<VerifyForm>
{({ isDirty, isInvalid, form, collect }) => (
  <div>
    <VerifyField
      value={this.state.username}
      onChange={this.handleChange}
      delegate={collect}
      name='username'
      required
    >
      {({ tail }) => (
        <div>
          <input type='text' { ...tail } />
          {isDirty && isInvalid && !form.username.isRequired && <span>Please enter a username</span>}
        </div>
      )}
    </VerifyField>
    <VerifyField
      value={this.state.password}
      onChange={this.handleChange}
      delegate={collect}
      name='password'
      required
    >
      {({ tail }) => (
        <div>
          <input type='text' { ...tail } />
          {isDirty && isInvalid && !form.password.isRequired && <span>Please enter a password</span>}
        </div>
      )}
    </VerifyField>
  </div>
)}
<VerifyForm>

VerifyField

This component can helps you detect user's enter in a input element.

Props

VerifyField component receive a render props function as a its children.

VerifyField currently support the props below:

• value: The input field value
• required: This property specifies that the user must fill in a value
• number: This property specifies that the user fill in a number
• email: This property specifies that the user fill in a email address
• url: This property specifies that the user fill in a URL
• minLength: This property specifies the minimum number of characters (in UTF-16 code units) that the user can enter
• maxLength: This property specifies the maximum number of characters (in UTF-16 code units) that the user can enter
• pattern: You can provide a custom a regular expression that the control's value is checked against
• validator: You can provide a custom validate function that the control's value is checked against
• focus: Check if the user is focused or blured on the input
• blur: Check if the user is focused or blured on the input
• debounce: Detecting the frequency of input changes. The default is 200 milliseconds
• delegate: This property specifies a function that VerifyForm have provided. When you use this property, the validation result of the VerifyField will be provided by VerifyForm.

Validate Results

The render props function will receive an object that is validated by the above props you provided. You can view this validation results as follows.

 <VerifyField>
  {(validateResults) => (
    <div>
      <div><input /></div>
      <pre>
        {JSON.stringify(validateResults, null, 2)}
      </pre>
    </div>
  )}
 </VerifyField>

// Based on the property you provide to the VerifyField
// validateResults may have the following structure
{
  isValid,
  isInvalid,
  isDirty,
  isRequired,
  isNumber,
  isEmail,
  isUrl,
  isValidMinLength,
  isValidMaxLength,
  isValidByPattern,
  isValidByValidator,
  isFocus,
  isBlur,
  tail
}

Notes

1. tail

You can pass anything to the VerifyField component. But the VerifyField component will only receive the props above, and assigns the remaining props and value prop to the tail. You can allocate it to input element like <input {...tail} /> to avoid writing some props repeatedly.

// value prop are repeated in <VerifyField /> and <input />
<VerifyField value={this.username} required >
  {({ isRequired }) => (
    <input type='text' name='username' value={this.username} onChange={this.handleChange} />
  )}
</VerifyField>

// The <input /> will be rendered like <input type='text' name='username' value={this.username} onChange={this.handleChange} />
<VerifyField
  type='text'
  name='username'
  value={this.username}
  onChange={this.handleChange}
  required
>
  {({ isRequired, tail }) => (
    <input { ...tail } />
  )}
</VerifyField>

// By the way, I think it is more semantic to write type on input element like <input type='text' {...tail} />

2. focus, blur

The effects of focus prop and blur prop are the same, just use one of them.

If you use focus or blur and want to handle focus or blur events in the input element, you have to pass handler to the VerifyField, otherwise the handler may fail.

// Do not do this
<VerifyField value={this.state.username} onChange={this.handleChange} focus>
  {() => <input type='text' onFocus={this.focusHandler} onBlur={this.blurHandler} />}
</VerifyField>

// You should do so
<VerifyField
  value={this.state.username}
  onChange={this.handleChange}
  onFocus={this.focusHandler}
  onBlur={this.blurHandler}
  focus
>
  {({ tail }) => <input type='text' {...tail} />}
</VerifyField>

VerifyForm

This component needs to work with VerifyField. It can helps you detect user's enter in all input elements.

Props and validation results

VerifyForm component only receive a render props function as a its children.

The validation results of all VerifyField will be collected by VerifyForm.

<VerifyForm>
  {({ isDirty, isValid, isInvalid, form, collect }) => (
    <div>
      {/* The form parameter contains all validation results */}
      <VerifyField name='username' delegate={collect} required focus >
        {({ isFocus, isBlur, tail }) => (
          <div>
            <input type='text' {...tail}/>
            {isInvalid && !form.username.isRequired && <span>Please enter a username</span>}
          </div>
        )}
      </VerifyField>
    </div>
  )}
</VerifyForm>

Notes

1. collect

You have to pass collect to the delegate of the VerifyField. Because the VerifyForm does not have a validation function, it can only collect the validation results of the VerifyField.

2. isInvalid

You need to use isInvalid before using the form parameter. Because the form parameter is empty when the VerifyForm is rendered for the first time.