keepDefined

interface Config {
  host?: string;
  port?: number;
  user?: string;
  password?: string;
}

const config: Config = {
  host: 'localhost',
  port: undefined,
  user: 'admin',
  password: undefined
};

const definedConfig = keepDefined(config, 'host', 'port', 'user', 'password');
// Result: { host: 'localhost', user: 'admin' }