How to access state from components to the parent component - reactjs

Question

I have a form in which all input, select tags are separate components and each component but the submit button is in the form it self like-
<form>
<InputComp1 />
<InputComp2 />
<Select1 />
<Select2 />
<button type='submit' value='Register'/>
</form>
So how do I collect all state from various components and when user clicks on the submit the values get submitted.?
Is this approach while dealing with forms right? or should I manage state of all tags in the same component?

Answer 1

Manage the state of all inputs/selects in this component. You can pass values and handler functions to the inputs using props.

Answer 2

There is no "right" approach, the answer depends on the context.
You can have form as a controlled component, where you manage the state of all tags (while passing callbacks down the tree) as you suggested and as mentioned in docs.
Or, you can have it as uncontrolled component, for example:
const Input = ({ name }) => {
return <input name={name} />;
};
const Component = () => {
return (
<>
<form
onSubmit={(e) => {
e.preventDefault();
const data = new FormData(e.target);
const entries = data.entries();
for (let entry of entries) {
console.log(entry);
}
}}
>
<Input name="username" />
<Input name="email" />
<input type="submit" value="Submit" />
</form>
</>
);
};
See controlled vs uncontrolled components.

Answer 3

Yes you should manage the state in the parent component itself and pass the onchange handler and value of that field as props inside the child components to update the value of the form fields.

Answer 4

Solution #1 would be "manage state react way". With this you should store state you need to share between components somewhere in their common ancestor. In your case it would be component that holds Form
Solution #2 applicable only if you use real form and form controls. Handle 'submit' event from the form and get all you need to submit from form data.
Solution #3 applicable only if you use some sort of "state manager". Follow instructions and best practices of the library you use.
In some cases you can mix and match that solutions. For example I still recommend to handle 'submit' event on form regardless of solution.

Answer 5

there is a concept of state lifting in react:
create a controlled form here and for every child, component pass a function to get the data from child components to parent one. by doing this you can submit all the values once.
here is the example
import React, {useState} from 'react';
const ChildInput = ({onChange, id}) => {
return(
<input
key={id}
type="text"
placeholder="enter name"
onChange={onChange}
/>
)
}
const Parent = () => {
const [name, setName] = useState('');
const onSubmit =(e)=>{
e.preventDefault();
// append your all data here just like child component
data = {name}
}
return(
<form onSubmit={onSubbmit}>
<ChildInput onChange={()=>setName(e.target.value)} id="name" />
<button type="submit" value="submit"/>
</form>
)}
for more information check this one: https://reactjs.org/docs/glossary.html#controlled-vs-uncontrolled-components