通过异步 API 调用在 React Context 中设置数据

Question

我正在尝试使用 GET API 请求使用来自后端的数据初始化自定义 React 上下文。但是，上下文在 API 调用完成数据获取之前加载。

我尝试过使用消费者向子组件发送数据，但我只能访问上下文的默认值，该默认值是在创建上下文时设置的。

这是我尝试设置上下文数据的方式

import React, {useState,useEffect} from "react";
import {callAffiliateApi} from "./services/affiliateService/transactionContext";

export const AffiliateContext = React.createContext("Raaaaaaaaaaaa");

export const AffiliateProvider  = ({children}) => {

  const [data, setData] = useState(null);
  useEffect(()=> {
    async function fetchData() {
      const newText = await callAffiliateApi();
      setData(newText)
    };fetchData()
  },[])

  console.log("Data in the context", data);
  if(data != null){
    return (
      <AffiliateContext.Provider value={data}>
        {children}
      </AffiliateContext.Provider>
    )}
  else {
    return (
      <AffiliateContext.Provider value={"Loading..."}>
        {children}
      </AffiliateContext.Provider>)
  }

}

这是我尝试在子组件中访问它的方式

import {AffiliateContext} from "../../../../AffiliateContext";

class Profile extends Component {


  constructor(props) {
    super(props);
    this.state = {
      text: this.props.text,
      user: this.props.user,

    }

  }

  render() {
    return (
    <AffiliateContext.Consumer>
      {data =>
        <div>
        {data}
      </div>}
    </AffiliateContext.Consumer>
      )
  }
}
export default Profile;

但是，页面中唯一显示的是组件的默认值 "Raaaaaaa"。如何让子组件等待数据从 API 请求中获取完成？

Answer 1

尝试使用 useContext 它的清洁器并尽量不要在 useEffect 中使用异步！

their related issues

import React, { useState,useEffect,useContext } from "react";
import { callAffiliateApi } from "./services/affiliateService/transactionContext";

const Context = React.createContext({});
const AffiliateContext = init => useContext(Context);

export const AffiliateProvider  = ({children}) => {

  const [data, setData] = useState(null);
  const [loading,setLoading]=useState(false);

  const getAffiliates = async ()=>{
    setLoading(true)
    const newText = await callAffiliateApi();
    setData(newText)
    setLoading(false)
  }

  useEffect(()=> {
    getAffiliates()
  },[])


    return (
      <AffiliateContext.Provider value={{loading,list:data}}>
        {children}
      </AffiliateContext.Provider>
    )
}

通过异步 API 调用在 React Context 中设置数据

Set the data in React Context from asynchronous API call

rest

synchronization

asynchronous

reactjs