Javascript 从 React-Native 应用程序中的另一个类访问静态变量？
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Access static variable from another class in React-Native app?
提问by user3802348
in my react-native app I currently have a User class in which I define a current user as below:
在我的本机应用程序中，我目前有一个 User 类，我在其中定义了一个当前用户，如下所示：
class User {
static currentUser = null;
//other relevant code here
static getCurrentUser() {
return currentUser;
}
}
export default User;
In a different class, I am trying to access the set value of this currentUser. I cannot figure out how to correctly call this function; I am getting the error User.getCurrentUser is not a function. Should I be calling this function in a different way?
在另一个类中，我试图访问此 currentUser 的设置值。我不知道如何正确调用这个函数；我收到错误User.getCurrentUser is not a function。我应该以不同的方式调用这个函数吗？
var User = require('./User');
getInitialState: function() {
var user = User.getCurrentUser();
return {
user: user
};
},
采纳答案by Balázs édes
You are mixing import/ exportstyles. You should either change your import to
你正在混合import/export风格。您应该将导入更改为
var User = require('./User').default
or
或者
import User from './User'
Or change your export:
或更改您的导出：
module.exports = User
回答by FlorianE
I think you also forgot the thiskeyword for returning the static "currentUser" field:
我认为您还忘记了返回静态“currentUser”字段的this关键字：
class User {
constructor() {}
static currentUser = {
uname: 'xxx',
firstname: 'first',
lastname: 'last'
};
static getCurrentUser() {
return this.currentUser;
}
}
console.log(User.getCurrentUser());
回答by OAslan
Try arrow function:
尝试箭头函数：
class User {
static currentUser = null;
static getCurrentUser = () => {
return currentUser;
}
}
export default User;
