export function startsWith (stringContent: string, pattern: string): boolean {
  if (typeof stringContent !== 'string') {
    console.warn('Trying to test a non string variable');
    return false;
  }
  return stringContent.indexOf(pattern) === 0;
}

export function capitalize (value: string): string {
  const firstLetter = value.substr(0, 1);
  const rest = value.substr(1, value.length - 1);
  return firstLetter.toUpperCase() + rest.toLowerCase();
}

// https://juhanajauhiainen.com/posts/how-to-make-typescript-understand-array-filter
export function isString (value: any): value is string {
  return typeof value === 'string';
}