剩余参数语法

function(...args){

}

function sum(...theArgs) {
  return theArgs.reduce((previous, current) => {
    return previous + current;
  });
}
 
console.log(sum(1, 2, 3));
// expected output: 6
 
console.log(sum(1, 2, 3, 4));
// expected output: 10