stitch-ui/src/home/validation.js

const VALID_APP_NAME_REGEXP = new RegExp("^[a-zA-Z0-9][a-zA-Z0-9-_]*$");

const validateAppName = appName => {
  if (appName.length === 0) {
    return "App name must not be empty";
  }
  if (appName.length > 63) {
    return "App name is too long";
  }
  if (!appName.match(VALID_APP_NAME_REGEXP)) {
    return "App name must be alphanumeric";
  }
  return null;
};

export default validateAppName;