fullstackopen-notes/parts/2/renderingCollections/src/App.jsx

import { useState } from "react";
import Note from "./components/Note";

const App = ({ startingNotes }) => {
  const [notes, setNotes] = useState(startingNotes);
  const [newNote, setNewNote] = useState("a new note...");
  const [showAll, setShowAll] = useState(true);

  const addNote = (event) => {
    event.preventDefault();
    const newNoteObject = {
      content: newNote,
      important: Math.random() < 0.5,
      id: String(notes.length + 1),
    };

    setNotes(notes.concat(newNoteObject));
    setNewNote("");
  };

  const handleNoteChange = (event) => {
    console.log(event.target.value);
    setNewNote(event.target.value);
  };

  const notesToShow = showAll
    ? notes
    : notes.filter((note) => note.important === true);

  return (
    <div>
      <h1>Notes</h1>
      <div>
        {" "}
        <button onClick={() => setShowAll(!showAll)}>
          {" "}
          show {showAll ? "important" : "all"}{" "}
        </button>{" "}
      </div>
      <ul>{notesToShow.map((note) => Note({ note }))}</ul>
      <form onSubmit={addNote}>
        <input value={newNote} onChange={handleNoteChange} />
        <button type="submit">save</button>
      </form>
    </div>
  );
};

export default App;