Question

我正在尝试使用async / await从诺言中检索结果，但是收到以下错误：

544：1未捕获的错误：模块构建失败：语法错误：等待是保留字（30:23）

这是我的代码：

import React from 'react';
import Header from './Header';
import Feed from './Feed';
import _ from 'lodash';
const Cosmic = require('cosmicjs')();

export default class WhereSheGoes extends React.Component {
    constructor (props) {
        super(props);
        this.state = {
            destinations: '',
            posts: '',
            globals: '',
        }
    }
    render() {
        const bucket = Cosmic.bucket({
            slug: 'where-she-goes',
            read_key: '',
            write_key: ''
        });
        const retrieveBucket = async () => {
            try {
                let result = bucket.getBucket()
                return result
            } catch (err) {
                console.log(err)
            }
        }
        const result = await retrieveBucket()
        console.log(result)
        this.setState (() => {
            return {
                destinations: _.filter(result.bucket.objects, {type_slug: 'destinations'}),
                posts: _.filter(result.bucket.objects, {type_slug: 'posts'}),
                globals: _.filter(result.bucket.objects, {type_slug: 'globals'})
            }
        });
        return (
            <div>
                <Header 
                    destinations={this.state.destinations}
                    posts={this.state.posts}
                    globals={this.state.globals}
                />
                <Feed
                    posts={this.state.posts}
                    destinations={this.state.destinations}
                />
            </div>
        );
    }
}

只有在返回结果并在实际的异步函数中设置状态后，我才能使以上代码运行。如何在该函数之外返回承诺的结果？

谢谢！

Answer 1

await只能在用async声明的函数中使用。因此，您应该在此函数内使用await来获取数据并设置状态。同样，您的代码也不是最佳的，因为它将尝试在每次重新呈现组件时接收数据。更好地构造您的类，并使用诸如componentDidMount之类的生命周期方法来获取数据并将其存储到状态。然后在渲染中只需使用状态即可显示

export default class WhereSheGoes extends React.Component {
    constructor (props) {
        super(props);
        this.state = {
            destinations: '',
            posts: '',
            globals: '',
        }
    }

    componentDidMount() {
        retrieveBucket();
    }

    retrieveBucket = async () => {
        const bucket = Cosmic.bucket({
            slug: 'where-she-goes',
            read_key: '',
            write_key: ''
        });
       try {
          let result = await bucket.getBucket()
          console.log(result)
          this.setState ({
                destinations: _.filter(result.bucket.objects, {type_slug: 'destinations'}),
                posts: _.filter(result.bucket.objects, {type_slug: 'posts'}),
                globals: _.filter(result.bucket.objects, {type_slug: 'globals'})
            });
       } catch (err) {
            console.log(err)
       }
    }

    render() {
        return (
            <div>
                <Header 
                    destinations={this.state.destinations}
                    posts={this.state.posts}
                    globals={this.state.globals}
                />
                <Feed
                    posts={this.state.posts}
                    destinations={this.state.destinations}
                />
            </div>
        );
    }
}```

Answer 2

您只能在异步函数中使用await。

您也可以使用.then

从'react'导入React；从'./Header'导入Header；从“ ./Feed”导入Feed；从'lodash'导入_； const Cosmic = require（'cosmicjs'）（）;

export default class WhereSheGoes extends React.Component {
    constructor (props) {
        super(props);
        this.state = {
            destinations: '',
            posts: '',
            globals: '',
        }
    }

    retriveBucket = () => {
      const bucket = Cosmic.bucket({
          slug: 'where-she-goes',
          read_key: '',
          write_key: ''
      });

      try {
        bucket.getBucket().then(result => {
          this.setState (() => {
              return {
                  destinations: _.filter(result.bucket.objects, {type_slug: 'destinations'}),
                  posts: _.filter(result.bucket.objects, {type_slug: 'posts'}),
                  globals: _.filter(result.bucket.objects, {type_slug: 'globals'})
              }
          });
        });
      } catch (err) {
          console.log(err)
      }
    }

    render() {
        this.retriveBucket();

        return (
            <div>
                <Header 
                    destinations={this.state.destinations}
                    posts={this.state.posts}
                    globals={this.state.globals}
                />
                <Feed
                    posts={this.state.posts}
                    destinations={this.state.destinations}
                />
            </div>
        );
    }
}

尝试检索异步/等待的结果

2 个答案: