语法错误：setter 函数必须有一个参数

¥Message

SyntaxError: Setter must have exactly one formal parameter. (V8-based)
SyntaxError: Setter function argument must not be a rest parameter (V8-based)
SyntaxError: setter functions must have one argument (Firefox)
SyntaxError: Unexpected token ','. setter functions must have one parameter. (Safari)
SyntaxError: Unexpected token '...'. Expected a parameter pattern or a ')' in parameter list. (Safari)

¥Error type

¥What went wrong?

set 属性语法看起来像一个函数，但它更严格，并且并非所有函数语法都允许。setter 始终只使用一个参数调用，因此使用任何其他数量的参数定义它都可能是错误的。此参数可以是 destructured 或具有 默认值，但不能是 剩余参数。

¥The set property syntax looks like a function, but it is stricter and not all function syntax is allowed. A setter is always invoked with exactly one argument, so defining it with any other number of parameters is likely an error. This parameter can be destructured or have a default value, but it cannot be a rest parameter.

请注意，此错误仅适用于使用 set 语法的属性设置器。如果你使用 Object.defineProperty() 等定义 setter，则 setter 被定义为普通函数，尽管如果 setter 需要任何其他数量的参数，它仍可能是一个错误，因为它将只使用一个参数被调用。

¥Note that this error only applies to property setters using the set syntax. If you define the setter using Object.defineProperty(), etc., the setter is defined as a normal function, although it's likely still an error if the setter expects any other number of arguments, as it will be called with exactly one.

¥Examples

¥Invalid cases

const obj = {
  set value() {
    this._value = Math.random();
  },
};

¥Valid cases

// You must declare one parameter, even if you don't use it
const obj = {
  set value(_ignored) {
    this._value = Math.random();
  },
};

// You can also declare a normal method instead
const obj = {
  setValue() {
    this._value = Math.random();
  },
};

¥See also

• 函数
• set