Form validation with react and material-ui

Does the check have to happen after a certain delay? A solution that I think would suffice in most situations would be to split your code up a bit. Don't trigger your isDisabled() function in changedValue(). Instead have it run on the onBlur event instead.

Try this:

<TextField
  hintText="Password"
  floatingLabelText="Password"
  type="password"
  errorText={this.state.password_error_text}
  onChange={e => this.changeValue(e, 'password')}
  onBlur={this.isDisabled} 
/>

and then your function becomes:

changeValue(e, type) {
    const value = e.target.value;
    const nextState = {};
    nextState[type] = value;
    this.setState(nextState);
}

Current Material-UI version doesn't use the errorText prop but there is still a way that you can use to display error and apply validation to the TextField in Material-UI.

We use the error(Boolean) property to denote if there is an error or not. Further to display the error text use helperText property of the TextField in the Material-UI, just provide it the error text you want to display.

Do it like:

<TextField
  value={this.state.text}
  onChange={event => this.setState({ text: event.target.value })}
  error={text === ""}
  helperText={text === "" ? 'Empty!' : ' '}
/>