Как сопоставить {0}, но обеспечить правильный выход?

function format(template, ...values) {
  const regex = /(?<=(?<!\{)(?:\{\{)*)\{\d+}(?!(?:}})*}(?!}))/g;
  return template.replace(regex, ([, index]) => {
    const valueIndex = parseInt(index, 10);
    if (valueIndex >= values.length) throw new Error("Not enough arguments")
    return String(values[valueIndex]).replaceAll('{{','{').replaceAll('}}','}');

  });
}

console.info([
  format("{0}", 42), // output `42`
  format("{0} {1}", 42, "bar"), // output `42 bar`
  format("{1} {1}", 42, "bar"), // output `bar bar` ({0} ignored)
  format("{{0", 42), // output `{0` (`{{` is an escaped `{`)
  format("{{{0}", 42), // output `{42` : an escaped brace and the formatted value
  format("Mix {{0}} and {0}", 42), // outputs `Mix {0} and 42`
]);

try {
  format("{0} {1}", 42); // throw error because not enough argument are passed
} catch (e) {
  console.error(e);
}

function format(template, ...values) {
  const regex = /{(\d+)}|([{}])(\2?)/g;
  return template.replace(regex, (_, index, brace, escaped) => {
    if (escaped) return brace;
    if (brace) throw new Error("Unescaped literal brace");
    if (+index >= values.length) throw new Error("Not enough arguments");
    return values[+index];
  });
}


const tests = [
  ["{0}", 42], // output `42`
  ["{0} {1}", 42, "bar"], // output `42 bar`
  ["{1} {1}", 42, "bar"], // output `bar bar` ({0} ignored)
  ["{{0", 42], // output `{0` (`{{` is an escaped `{`)
  ["{{{0}", 42], // output `{42` : an escaped brace and the formatted value
  ["Mix {{0}} and {0}", 42], // outputs `Mix {0} and 42`
  ["Invalid closing brace }"], // should fail, since the closing brace does not close an opening one
  ["Invalid placeholder {z}"], // should fail, not an integer
  ["{0}", "With { in value"], // output `With { in value`, inner { should be broke the format
  ["{0} {1}", 42], // throw error because not enough argument are passed
];

for (const [test, ...args] of tests) {
  try {
    console.info(format(test, ...args));
  } catch (e) {
    console.info("Error:", e.message);
  }
}