useState 未在 array.map() 内更新。响应式JS

Question

我正在尝试通过在 array.map 中使用 useState 添加数组的值，但这些值没有更新

function App() {
  const [ingredients, setIngredients] = useState([]);
  
  const getIngredients = (data) => {
    data.map((item, i) => {
      console.log(data[i]);
      setIngredients([...ingredients, data[i]]);
     // setIngredients([...ingredients, item]); <- Also doesnt work 
      console.log(ingredients);
    });

Console.log(数据)

(26) ["Product", "Information↵NUTELLA", "HAZELNUT", "SPREAD", "↵Total:", "↵aty:", "↵BARILLA", "SPAGHETTI", "Z↵Total:", "↵CLASSICO", "CRMY", "ALFERO", "DI", "ROMA", "PENNE", "RIGATE", "PASTA", "↵Order", "Summary↵item", "Subtotat", "↵Sales", "Tax", "Total:", "", "↵", Array(0)]

console.log(成分);

[]

console.log(项);

Lists out all the items one after the other

Answer 1

setState 是异步的，因此它不能保证更新之前的状态，因此将一个函数传递给 setState 以使其工作。

setIngredients((ingredients) => [...ingredients, data[i]]);

useState 未在 array.map() 内更新。响应式JS

useState is not updating inside array.map(). ReactJS

arrays

reactjs

use-state