react-use-validated-state

React hook for using state with validation. Uses validate.js

---

Syntax

const [state, setState, isValid, validationMessage, validate] =
       useValidatedState(initialState, getValidationMessage, validateImmediately]);

Returns a stateful value, a function to update it, whether it's valid, and validation message (if invalid).

Parameters

initialState The initial state value. During the initial render, the returned state is the same as this value.

getValidationMessage Optional. Function that receives the current state value, and returns a validation string if invalid, otherwise should return undefined;

Default value: () => undefined

validateImmediately Optional. Boolean value whether to validate on initial render, otherwise will validate after first change.

Default value: false

Return values

state The current state value.

setState Function used to update the state. It accepts a new state value and enqueues a re-render of the component.

isValid A boolean value indicating if the state passes the validationConstraints. Returns undefined if validation has not been been run.

validationMessage Optional. A string describing the validation failures, if any.

validate Optional. Function used to trigger validation, even if state is unchanged. Useful for validating an unchanged value on blur.

Usage

const [username, setUsername, usernameValid, usernameValidationMessage, validateUsername] =
       useValidatedState('', { presence: true, email: true });
const [pwd, setPwd, pwdValid, validatePwd] =
       useValidatedState(password, { presence: true, length: { minimum: 6 } });
 
return (
  <form>
    <div>
      <label>Username</label>
      <input
        value={username}
        onChange={e => setUsername(e.target.value)}
        onBlur={() => validateUsername()}
      />
      <div>{usernameMessage}</div>
    </div>
    <div>
      <label>Password</label>
      <input
        type="password"
        value={pwd}
        onChange={e => setPwd(e.target.value)}
        onBlur={() => validatePwd()}
      />
      <div>{pwdMessage}</div>
    </div>
    <input type="submit" disabled={usernameValid && pwdValid} value="Sign Up" />
  </form>
);