Answer to user's question

make error in render

class SignUpForm extends React.Component {
// other stuff
    render()
    const shouldMarkError = (field) => {
      const hasError = errors[field];
      const shouldShow = this.state.touched[field];

      return hasError ? shouldShow : false;
    };

    // ...

    <input
      className={shouldMarkError('email') ? "error" : ""}
      onBlur={this.handleBlur('email')}

      type="text"
      placeholder="Enter email"
      value={this.state.email}
      onChange={this.handleEmailChange}
    />
  }
}

make error outisde render

class SignUpForm extends React.Component {
// other stuff
    shouldMarkError(field){
      const hasError = errors[field];
      const shouldShow = this.state.touched[field];

      return hasError ? shouldShow : false;
    };
    
    render()


    // ...

    <input
      className={this.shouldMarkError('email') ? "error" : ""}
      onBlur={this.handleBlur('email')}

      type="text"
      placeholder="Enter email"
      value={this.state.email}
      onChange={this.handleEmailChange}
    />
  }
}