通过输入传递道具 - React

Question

Within a child component I have state to store input.

My goal is to pass the input state to the parent component.

    //Child component 

    const [userInput, setUserInput] = useState("");

    <TextField value={input} onInput={e => setInput(e.target.value)} />

I tried creating a function to be called on input within the parent function but I cannot seem to get the value "input" passed. What is the correct way to do this? Thanks!

Answer 1

You can move the state to the parent component. Then pass the props from the child to the parent.

function Child({
    ...rest
}) {
    return <TextField {...rest} />
}
function Parent() {
    const [input, setInput] = useState(''); // '' is the initial state value
    return (
        <Child  value={value} onInput={e => setInput(e.target.value)} />
    )
}

Answer 2

you were approaching correctly. You can pass a function to get the data from the child to the parent. Check this example:

import { useState } from "react";
import "./styles.css";

export default function App() {
  const [text, setText] = useState("");

  const getInput = (t) => {
    console.log(t);
    setText(t);
  };

  return (
    <div className="App">
      <Component getInput={getInput} value={text} />
      <p>{text}</p>
    </div>
  );
}

const Component = ({ getInput, value }) => {
  return (
    <>
      <h1> Test </h1>
      <input type="text" value={value} onChange={(e) => getInput(e.target.value)}></input>
    </>
  );
};

The parent App is retrieving the text from the child Component passing the function getInput . You only have to decide with event you want to detonate. Of course, this is with input not with TextField. I think that you are using TextField from React Material UI, if that's the case you may check the docs to know how to trigger an event.

Answer 3

I finally figured this out.

// This is in the parent component 

const [userInput, setUserInput] = useState("");

// Step 1: Create a function that handles setting the state 
const inputHandler = (userInput) => {
setUserInput(userInput);
}

<PhaseTwoTemplate onInput={inputHandler}  />
//Step 2: Add a function that calls the handler

...

// This is the child component PhaseTwoTemplete.js

const [input, setInput] = useState(""); 
// This second state holds the input data for use on child component
// It also is an easy way to hold the data for the parent function. 

 
<TextField 
onChange={e => setInput(e.target.value)}
value={input}  
onInput={onInputHandler} 
/>

// Step 3: Pass the user input to the parent
const onInputHandler = () => {
props.onInput(input);
}