this.props在子组件的console.log中工作，但不渲染

Question

I'm passing a recently updated state variable to a child component. In that child component I'm able to console.log(this.props.response.message) and see the expected result of the recently updated variable. However, the this.props.response.message is not rendering. Do I need to perform some action in a React Lifecycle method? If so, which one and how would that look?

Parent Component

 import React, { Component } from 'react'; import axios from 'axios'; import FormSuccess from './FormSuccess'; export default class NewRuleForm extends Component { constructor(props) { super(); this.state = { submitSuccess: false, isOpen: false, response: {} }; this.handleSubmit = this.handleSubmit.bind(this); } async handleSubmit(e) { let response = await axios.post('localhost:5000', { data: e.target.id.value } ) if (response.data.success) { this.setState({ submitSuccess: true, response: response.data }) } else { this.setState({ submitSuccess: false, }) } return response } } render() { if (this.state.submitSuccess === true) { return <FormSuccess result={this.state.response} /> } return ( <form onSubmit={this.handleSubmit}> <input type="text" name="id"/> </form> ) } } 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script> 

Child Component

 import React, { Component } from 'react'; export default class FormSuccess extends Component { constructor(props) { super(); } render() { console.log(this.props.result.message) // works return ( <div> <h1>Successful Form Submission</h1> {/* below doesn't render */} <p>{this.props.result.message}</p> </div> ); } } 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script> 

Again, in that child component I am able to console.log(this.props.response.message) and see the expected result of the recently updated variable. However, it does not render.

Answer 1

You are passing data in result prop,

<FormSuccess result={this.state.response} />

You should use it like this,

{this.props.result} // Normal case

If you are getting object in result and want to retrieve message from it then use this,

{this.props.result.message}

Answer 2

Also you should be careful about data type. If data type is json or something like that, you cant render it but you can write on console.