```ts
/**
 * The KEY=VALUE pairs of a config file.
 */
export function parseConfig(text: string): Record<string, string> {
  const config: Record<string, string> = {};
  for (const line of text.split("\n")) {
    const trimmedLine = line.trim();
    if (trimmedLine === "" || trimmedLine.startsWith("#")) continue;
    const [key, value] = trimmedLine.split("=", 2);
    if (!key) throw new Error(`Empty key on line: "${line}"`);
    config[key.trim()] = value?.trim() ?? "";
  }
  return config;
}
```