normalize.ts

function interpolate(strings: TemplateStringsArray, interpolations: unknown[]): string {
  return strings.reduce((interpolation, string, index) => (
    interpolation.concat(String(index), string);
  ));
}

function normalizeWhiteSpaces(strings: TemplateStringsArray, ...interpolations: unknown[]): string {
  const interpolation = interpolate(strings, interpolations);
  return interpolation.replace(/\s+/g, ' ').trim();
}

const user = {
  name: 'Vitor',
};

normalizeWhiteSpaces`
  Hi, ${user.name}!
  How are you doing?
`;
// => "Hi, Vitor! How are you doing?"