语法错误：剩余参数后的参数

¥Message

SyntaxError: Rest parameter must be last formal parameter (V8-based)
SyntaxError: parameter after rest parameter (Firefox)
SyntaxError: Unexpected token ','. Rest parameter should be the last parameter in a function declaration. (Safari)

¥Error type

¥What went wrong?

rest 参数必须是函数定义中的最后一个参数。这是因为 rest 参数收集了传递给函数的所有剩余参数，因此在它后面没有任何参数是没有意义的。下一个非空白字符必须是参数列表的右括号。

¥A rest parameter must be the last parameter in a function definition. This is because the rest parameter collects all the remaining arguments passed to the function, so it doesn't make sense to have any parameters after it. The next non-whitespace character must be the closing parenthesis of the parameter list.

¥Examples

¥Invalid cases

function replacer(match, ...groups, offset, string) {}

function doSomething(
  arg1,
  arg2,
  ...otherArgs, // Accidental trailing comma
) {}

¥Valid cases

function replacer(match, ...args) {
  const offset = args.at(-2);
  const string = args.at(-1);
}

function doSomething(arg1, arg2, ...otherArgs) {}

¥See also

• 函数
• 其余参数