Thanks to the setState() call, React knows the state has changed, and calls the render() method again to learn what should be on the screen. This time, this.state.date in the render() method will be …

We declare a state variable called count, and set it to 0. React will remember its current value between re-renders, and provide the most recent one to our function.

How do I update state with values that depend on the current state? Pass a function instead of an object to setState to ensure the call always uses the most updated version of state (see below).

setState() enqueues changes to the component state and tells React that this component and its children need to be re-rendered with the updated state. This is the primary method you use to update …

Los Hooks son una nueva incorporación en React 16.8. Te permiten usar estado y otras características de React sin escribir una clase. La página de introducción utilizó este ejemplo para familiarizarte con …

If you update a State Hook to the same value as the current state, React will bail out without rendering the children or firing effects. (React uses the Object.is comparison algorithm.)

setState 呼び出しは非同期です。 呼び出し直後から this.state が新しい値を反映することを期待しないでください。 もし現在の state に基づいた値を計算する必要がある場合は、オブジェクトの代わり …

Почему React не обновляет this.state синхронно? Как говорилось ранее, React намеренно «ждёт» пока все компоненты вызовут setState() в своих обработчиках событий прежде чем начать …

In React, sharing state is accomplished by moving it up to the closest common ancestor of the components that need it. This is called “lifting state up”. We will remove the local state from the …

Ví dụ trên khai báo một biến state gọi là count và set nó về 0. React sẽ nhớ giá trị hiện tại của nó và cung cấp cho hàm của chúng ta giá trị mới nhất giữa những lần re-render.