如何使用反应挂钩将数据从父级传递给子级

Question

I have a simple modal in which I have a form on submit I display errors now I want to pass these errors to the children component.

Here is a simplified parent component

import React from 'react';
import Input from 'components/Functional/Input';

function Parent() {
    const [errors, setErrors] = useState([]);
    const handleSubmit = async e => {
            const formData = new FormData();
    }

    return (
        <Modal handleSubmit={handleSubmit}>
           <Input setErrors={errors} ></Input>
        </Modal>
    )
}

export default Parent

Here is my children component

import React from 'react'

function Input({errors}) {
    const [field, setField] =useState('');

    console.log('errors', errors)
    return (
        <div>
            <input type="text"  onChange={e => setField(e.target.value)} />
        </div>
    )
}

export default Input

Now when I submit the data with errors, the console.log('errors', errors) in the children component I get undefined

What is wrong here?

Answer 1

Pay attention to props name. You're passing from parent a property called setErrors while in child component you're looking for errors . Try to rename property from setErrors to errors or simply read setErrors from <Input /> component

Answer 2

You seem to have a typo in your input component. You set the prop setErrors but your component expects errors . If you use plain javascript you should use proptypes to ensure this doesn't happen.

import React from 'react'
import PropTypes from 'prop-types'

function Input({errors}) {
    const [field, setField] =useState('');

    console.log('errors', errors)
    return (
        <div>
            <input type="text"  onChange={e => setField(e.target.value)} />
        </div>
    )
}

Input.propTypes = {
    errors: PropTypes.arrayOf(PropTypes.string)
};

export default Input

See PropTypes