Meteor/React - 如何等待 Meteor.user()

Question

我正在努力弄清楚如何等待 Meteor.user()在 react 组件中订阅。我知道用户已登录，因为 Meteor.userId()返回 _id ，但尝试访问电子邮件地址显示 Meteor.user()返回未定义。我猜是因为它还没有可用。

唉，由于 Meteor.user() 不是我手动订阅的发布，我不确定如何在 React 组件中等待它。有人可以指出我的例子吗？

import { Meteor } from 'meteor/meteor';
import React from 'react';
import { Link } from 'react-router';
import { createContainer } from 'meteor/react-meteor-data';

import './BaseLayout.scss';


class BaseLayout extends React.Component {

    constructor(props) {
        super(props);

        this.state = {
            isAuthenticated: (Meteor.userId() !== null) ? true : false,
        }
    }

    componentWillMount() {
        if (!this.state.isAuthenticated) {
            this.context.router.push('/login');
        }
    }

    componentDidUpdate(prevProps, prevState) {
        if (!this.state.isAuthenticated) {
            this.context.router.push('/login');
        }
    }

    toggleUserMenu() {
        this.refs.userMenu.style.display = (this.refs.userMenu.style.display === 'block') ? 'none' : 'block';
    }

    logout(e) {
        e.preventDefault();
        Meteor.logout();
        this.context.router.push('/login');
    }

    render() {
        return(
            <div id="base">
                <div id="header">
                    <div id="top-bar" className="clear-fix">
                        <div className="float-left" id="logo"></div>
                        <div className="float-right" id="user-menu">
                            <div onClick={this.toggleUserMenu.bind(this)}>
                                <span>{this.props.currentUser.emails[0].address}</span>
                                <div className="arrow-down"></div>
                            </div>
                            <div id="user-menu-content" ref="userMenu">
                                <a onClick={this.logout.bind(this)}>Sign Out</a>
                            </div>
                        </div>
                    </div>
                </div>
                <div id="bodyContainer">
                    {this.props.children}
                </div>
                <div id="footer">
                    <ul>
                        <li><a href="mailto:test@example.com">Made by Us</a></li>
                    </ul>
                </div>
            </div>
        )
    }
}
BaseLayout.contextTypes = {
    router: React.PropTypes.object.isRequired,
}


export default BaseLayoutContainer = createContainer(() => {

    var handle = Meteor.subscribe("user.classrooms");

    return {
        currentUser: Meteor.user(),
        dataLoading: !handle.ready(),
        classrooms: Classrooms.find({}).fetch(),
    };
}, BaseLayout);

Answer 1

您可以使用三元运算

currentUser ? true : flase

保持组件井井有条的另一个重要提示是始终 destructure例如，而不是做 const currentUser = this.props.currentUser你可以做 const { currentUser } = this.props;看一看:

render() {
const { currentUser, children } = this.props;
  return (
  <div id="base">
    <div id="header">
      <div id="top-bar" className="clear-fix">
        <div className="float-left" id="logo"></div>
        <div className="float-right" id="user-menu">
          <div onClick={this.toggleUserMenu.bind(this)}>
           {currentUser ?
             <span>{currentUser.emails[0].address}</span> :
             <span>Loading...</span>
           }
            <div className="arrow-down"></div>
          </div>
          <div id="user-menu-content" ref="userMenu">
            <a onClick={this.logout.bind(this)}>Sign Out</a>
          </div>
        </div>
      </div>
    </div>
    <div id="bodyContainer">
      {children}
    </div>
    <div id="footer">
      <ul>
        <li><a href="mailto:test@example.com">Made by Us</a></li>
      </ul>
    </div>
  </div>
)
}