So I'm doing a list in which you can add items. When you add them you have two options:

1. Delete the whole list
2. Delete a specific item.

But for some reason the "handeDelete" button is not working. Can somebody tell me what did I write wrong in the code?

The link to CodeSandbox is:

codesandbox

import { useState } from "react";
import uuid from "react-uuid";

export default function ItemList() {
const [items, setItems] = useState({ item: "" });
const [groceryList, setGroceryList] = useState([]);

function handleChange(value, type) {
setItems((prev) => {
  return { ...prev, [type]: value };
});
}

function handleSubmit(e) {
e.preventDefault();
const newItem = { ...items, id: uuid() };
setGroceryList([...groceryList, newItem]);
setItems({ item: "" });
}

function handleDelete(id) {
setGroceryList(groceryList.filter((items) => items.id !== id));
}

return (
<>
  <form autoComplete="off" onSubmit={handleSubmit}>
    <input
      type="text"
      name="item"
      id="item"
      value={items.item}
      onChange={(e) => handleChange(e.target.value, "item")}
    />
  </form>
  {groceryList.map((list) => {
    return (
      <div key={list.id}>
        <ul>
          <li> {list.item}</li>
        </ul>
        <button onClick={(id) => handleDelete()}>Delete</button>
      </div>
    );
  })}
  <button onClick={() => setGroceryList([])}>Clear</button>
  </>
 );
}

CodePudding user response：

Your delete button definition is wrong:

<button onClick={() => handleDelete(list.id)}>Delete</button>

the parameter you are receiving from the click event is not the id. Since you are not working with the event args itselfy you can safely ignore it. The second mistake was, that you are not passing the id itself to your handleDelete function.

For learning purposes, humor yourself and print the event to the console, while developing:

<button onClick={(evt) => {
          console.log(evt)
          handleDelete(list.id)
        }}>
    Delete
</button>

This will show you, that the parameter, that you named id (and I renamend to evt), is in fact reacts Synthetic Event: https://reactjs.org/docs/events.html