es6中selectedSubreddit(,a1)怎么传递参数为什么错误？

Question

function selectedSubreddit(state = 'reactjs', action) {    switch (action.type) {      case 'tr':        return '突然'        default:            return state    }}var a1 = {  type: 'tr'}let selected = selectedSubreddit(,a1);console.log(selected);function selectedSubreddit(action,state = 'reactjs') {    switch (action.type) {      case 'tr':        return '突然'        default:            return state    }}var a1 = {  type: 'tr'}let selected = selectedSubreddit(a1, );console.log(selected); // 突然

Answer 1

• 问题中的示例，有默认值的参数state并不是尾参数，所以无法只省略这个参数，解决方法可以调用时显示输入undefined，即let selected = selectedSubreddit(undefined, a1);

• 或者function selectedSubreddit(action, state = 'reactjs') { }，然后调用let selected = selectedSubreddit(a1, );