Reactda Inputlarni Massivga Bog‘lash

Holatda notes massivi saqlansin:

jsxfunction App() {
  const [notes, setNotes] = useState([1, 2, 3]);
  
  return <div>
    
  </div>;
}

Shuningdek, massiv elementlari yig‘indisini topadigan yordamchi funktsiyamiz bor:

jsxfunction getSum(arr) {
  let sum = 0;
  
  for (const elem of arr) {
    sum += +elem;
  }
  
  return sum;
}

function App() {
  ...
}

Keling, holatdagi massivimiz elementlari yig‘indisini topamiz va chiqaramiz, buning uchun yordamchi funktsiyamizdan foydalanamiz:

jsxfunction App() {
  const [notes, setNotes] = useState([1, 2, 3]);
  
  return <div>
    {getSum(notes)}
  </div>;
}

Keling, endi uchta input yaratamiz va har bir inputning value qismiga massivning elementlaridan birini yozamiz:

jsxfunction App() {
  const [notes, setNotes] = useState([1, 2, 3]);
  
  return <div>
    <input value={notes[0]} />
    <input value={notes[1]} />
    <input value={notes[2]} />
    
    {getSum(notes)}
  </div>;
}

Keling, endi inputlarimizga onChange hodisasini qo‘shamiz. Bunda bitta umumiy ishlovchi funktsiya yaratamiz:

jsxfunction App() {
  const [notes, setNotes] = useState([1, 2, 3]);
  
  function changeHandler(index, event) {
    // umumiy ishlovchi funktsiya
  }
  
  return <div>
    <input value={notes[0]} onChange={event => changeHandler(0, event)} />
    <input value={notes[1]} onChange={event => changeHandler(1, event)} />
    <input value={notes[2]} onChange={event => changeHandler(2, event)} />
    
    {getSum(notes)}
  </div>;
}

Ko‘rib turganingizdek, changeHandler funktsiyasi birinchi parametr sifatida massivning qaysi elementini tahrirlayotganini bildiruvchi raqamni qabul qiladi.

Ushbu raqam yordamida massiv elementini input mazmuni bilan almashtirishimiz mumkin.

Buni amalga oshiramiz:

jsxfunction changeHandler(index, event) {
  setNotes([...notes.slice(0, index), event.target.value, ...notes.slice(index + 1)]);
}

Endi istalgan inputni tahrirlash mumkin, shu bilan birga massiv reaktiv o‘zgaradi va uning elementlari yig‘indisi qayta hisoblanadi.

Keling, barcha kodimizni bir joyga to‘plab chiqamiz:

jsxfunction App() {
  const [notes, setNotes] = useState([1, 2, 3]);
  
  function changeHandler(index, event) {
    setNotes([...notes.slice(0, index), event.target.value, ...notes.slice(index + 1)]);
  }
  
  return <div>
    <input value={notes[0]} onChange={event => changeHandler(0, event)} />
    <input value={notes[1]} onChange={event => changeHandler(1, event)} />
    <input value={notes[2]} onChange={event => changeHandler(2, event)} />
    
    {getSum(notes)}
  </div>;
}

Inputlarni tsiklda yaratish mumkin:

jsxfunction App() {
  const [notes, setNotes] = useState([1, 2, 3]);
  
  function changeHandler(index, event) {
    setNotes([...notes.slice(0, index), event.target.value, ...notes.slice(index + 1)]);
  }
  
  const result = notes.map((note, index) => {
    return <input
      key={index}
      value={note}
      onChange={event => changeHandler(index, event)}
    />;
  });
  
  return <div>
    {result}
    {getSum(notes)}
  </div>;
}

jsx[1, 2, 3, 4, 5, 6, 7, 8, 9]