if else的优化

1.switch

2.3元表示式

3.用对象处理

let statusObj = {
    "hello": "您好",
    "world": "world"
}
let status = "hello";
console.log(statusObj[status]);
// 等同
let string = "";
if (status == "hello") {
    string = "您好";
} else if (status == "world") {
    string = "world";
}
console.log(string);

 4.使用map处理

var actions = new Map([
    [1, ['processing','IndexPage']],
    [2, ['fail','FailPage']],
    [3, ['fail','FailPage']],
    [4, ['success','SuccessPage']],
    [5, ['cancel','CancelPage']],
    ['default', ['other','Index']]
])

let action = actions.get(1)|| actions.get('default');
console.log(action[0]);
console.log(action[1]);

 注：尽量把可提取的东西提取出来，减少重复性的代码