Function append

http/unstable_cache_control.ts:362–394

(
  out: string[],
  directive: string,
  value?: number | true | string[],
)

}

function append(
  out: string[],
  directive: string,
  value?: number | true | string[],
): void {
  if (value === undefined) return;
  if (value === true) {
    out.push(directive);
    return;
  }
  if (typeof value === "number") {
    if (!Number.isInteger(value) || value < 0) {
      throw new RangeError(
        `Cache-Control: ${directive} must be a non-negative integer, got ${value}`,
      );
    }
    // Clamp to MAX_DELTA_SECONDS to match parser behavior (RFC 9111 §1.2.2).
    out.push(`${directive}=${Math.min(value, MAX_DELTA_SECONDS)}`);
    return;
  }
  if (value.length === 0) {
    out.push(directive);
    return;
  }
  for (const name of value) {
    if (!TCHAR_REGEXP.test(name)) {
      throw new TypeError(
        `Cache-Control: invalid field name in ${directive}: "${name}"`,
      );
    }
  }
  out.push(`${directive}="${value.join(", ")}"`);
}

/**
 * Serializes a Cache-Control object to a header value string. Output is