// 参数的默认值
function save(filename = throw new TypeError("Argument required")) {
}
// 箭头函数的返回值
lint(ast, {
  with: () => throw new Error("avoid using 'with' statements.")
});
function getEncoder(encoding) {
  const encoder = encoding === "utf8" ?
    new UTF8Encoder() :
    encoding === "utf16le" ?
      new UTF16Encoder(false) :
      encoding === "utf16be" ?
        new UTF16Encoder(true) :
        throw new Error("Unsupported encoding");
}
// 逻辑表达式
class Product {
    return this._id;
  }
  set id(value) {
    this._id = value || throw new Error("Invalid value");
  }
}