JavaScript:使用条件语句进行销毁 [英] JavaScript: destructuring with a conditional statement

问题描述

我想从整个user对象中获取firstName和lastName属性.我也需要使用条件语句. 该怎么做?

I would like to get firstName and lastName properties from a whole user object. I need to use a conditional statement too. How to do something like that?

getUserById(id)和getUserByAddress(id)使用返回元素或undefined的JavaScript find()方法.

getUserById(id)and getUserByAddress(id) use the JavaScript find() method that returns an element or undefined.

let { firstName, lastName } = getUserById(id);
if ({ firstName, lastName } === undefined) {
  { firstName, lastName } = getUserByAddress(id);
}
return `${firstName} ${lastName}`;

推荐答案

const { firstName, lastName } = getUserById(id) || getUserByAddress(id) || {};
if (firstName && lastName) {
    return `${firstName} ${lastName}`;
}
return "Unknown user";

如果getUserById(id)虚假，将执行getUserByAddress(id).如果这也是虚假的，则{}至少可以防止引发错误.

If getUserById(id) is falsy, getUserByAddress(id) will be executed. If this is falsy, too, {} will at least prevent throwing an error.

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