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Last active Sep 29, 2019
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import React, { useState, useEffect, useRef } from "react";
import ReactDOM from "react-dom";
function App() {
const [count, setCount] = useState(0);
const isFirstRun = useRef(true);
useEffect(() => {
if (isFirstRun.current) {
//skip firstRun
isFirstRun.current = false;
//here we are sure count has been change
console.log("count", count);
}, [count]);
return (
<div className="App">
<h1>counter: {count}</h1>
<button onClick={() => setCount(count => count + 1)}>
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);
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