React dynamic nested form input - reactjs

Question

Im a newbie in React and Im creating a simple form that sends data to DB. I made it work almost as I wanted, the only problem is that I dont know how to update the state which has an array inside.
The idea is to make a form so I can add recipes which include the whole recipe data that I map through to render each recipe. In the data object I need simple strings most of the time but then I need also three arrays or objects, I prefer the arrays in this case.
I found many solutions for class components but still I could figure out how to update the arrays. I even figured out how to update one array from a string input separated only with commas, then .split(', ') and .trim() and map() through but I could not setFormFields({}) at two places at the same time since the createRecipe() is async. The split just did not happen before the array was sent to the DB as a string. Thats why I dont put the whole code here.
I will simplify the code to make you see clear.
const defaultFormFields = {
title: '',
imageUrl: '',
leadText: '',
};
const NewRecipeForm = () => {
const [formFields, setFormFields] = useState(defaultFormFields);
const { title, imageUrl, leadText } = formFields;
const [ingredients, setIngredients] = useState([])
const handleFormFieldsChange = (event) => {
setFormFields({ ...formFields, [event.target.name]: event.target.value })
}
const handleIngredientsChange = ( event) => {
**// here I need help**
setIngredients()
}
const addIngredient = () => {
setIngredients([...ingredients, ''])
}
const removeIngredient = (index) => {
**// here I need help**
}
const createRecipe = async (event) => {
event.preventDefault()
// addRecipe sends the object to Firestore DB
addRecipe('recipes', url, formFields)
resetFormFields()
}
const resetFormFields = () => {
setFormFields(defaultFormFields);
};
return (
<NewRecipeFormContainer>
<h1>New recipe</h1>
<form onSubmit={createRecipe}>
<h1>Title</h1>
<input label='Title' placeholder='Recipe title' name='title' value={title} onChange={handleChange} />
<input label='imageUrl' placeholder='imageUrl' name='imageUrl' value={imageUrl} onChange={handleFormFieldsChange} />
<input label='leadText' placeholder='leadText' name='leadText' value={leadText} onChange={handleFormFieldsChange} />
<h1>Ingredients</h1>
**// here I need help ?**
{
ingredients.map((ingredient, index) => {
return (
<div key={index}>
<input label='Ingredience' placeholder='Ingredience' name='ingredient' value={ingredient.ingredient} onChange={handleChange} />
**// here I need help ?**
<button onClick={removeIngredient} >remove</button>
</div>
)
})
}
<button onClick={addIngredient} >add</button>
</form>
<Button onClick={createRecipe}>ODESLAT</Button>
</NewRecipeFormContainer>
)
}
I will appreciate any hint or help. Ive been totally stuck for two days. Thank you!

Answer 1

Here's an example of how to update a single element in a list.
const updateSingleItemInList = (index, update) => {
setList(list.map((l, i) => i === index ? update : l));
};
const add = (element) => setList([...list, element]);
Try simplifying your state first:
const [ingredients, setIngredients] = useState([]);
const [tips, setTips] = useState([]);
Then it becomes simple to write the handlers:
const updateIngredient = (index, text) => {
setIngredients(list.map((ing, i) => i === index ? text : ing));
};
const addIngredient = () => setIngredients([...ingredients, ""]);
Then you can create the form object when the user wants to submit:
addRecipe('recipes', url, {
ingredients: ingredients.map(i => ({ingredients: i})),
// etc.
});
Put it all together and here is the minimum viable example of a component that manages a dynamic number of form elements (tested, works):
export const TextBody = () => {
const [list, setList] = useState([{ name: "anything" }]);
const add = () => setList(l => [...l, { name: "" }]);
const remove = i => setList(l => [...l.slice(0, i), ...l.slice(i + 1)]);
const update = (i, text) => setList(l => l.map((ll, ii) => (ii === i ? { name: text } : ll)));
return (
<>
<TouchableOpacity onPress={add}>
<Text text="add" />
</TouchableOpacity>
{list.map((l, i) => (
<>
<Text text={JSON.stringify(l)} />
<TouchableOpacity onPress={() => remove(i)}>
<Text text="remove" />
</TouchableOpacity>
<Input onChange={c => update(i, c.nativeEvent.text)} />
</>
))}
</>
);
};
You can return those CRUD functions and the state from a custom hook so you only have to write this once in a codebase.
Edit: Just for fun, here's the same component with a reusable hook:
const useListOfObjects = (emptyObject = {}, initialState = []) => {
const [list, setList] = useState(initialState);
const add = () => setList(l => [...l, emptyObject]);
const remove = i => setList(l => [...l.slice(0, i), ...l.slice(i + 1)]);
const update = (i, text, field) =>
setList(l => l.map((ll, ii) => (ii === i ? { ...ll, [field]: text } : ll)));
return {
list,
add,
remove,
update,
};
};
export const TextBody = () => {
const { list, add, remove, update } = useListOfObjects({ name: "", id: Math.random() });
return (
<>
<TouchableOpacity onPress={add}>
<TextBlockWithShowMore text="add" />
</TouchableOpacity>
{list.map((l, i) => (
<React.Fragment key={`${l.id}`}>
<TextBlockWithShowMore text={JSON.stringify(l)} />
<TouchableOpacity onPress={() => remove(i)}>
<TextBlockWithShowMore text="remove" />
</TouchableOpacity>
<Input onChange={c => update(i, c.nativeEvent.text, "name")} />
</React.Fragment>
))}
</>
);
};