react-hooks: skip first run in useEffect [duplicate]
The useRef hook can be used to store any mutable value, so you could store a boolean indicating if it's the first time the effect is being run.
Example
const { useState, useRef, useEffect } = React;
function MyComponent() {
const [count, setCount] = useState(0);
const isFirstRun = useRef(true);
useEffect (() => {
if (isFirstRun.current) {
isFirstRun.current = false;
return;
}
console.log("Effect was run");
});
return (
<div>
<p>Clicked {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<MyComponent/>,
document.getElementById("app")
);<script src="https://unpkg.com/[email protected]/umd/react.development.js"></script>
<script src="https://unpkg.com/[email protected]/umd/react-dom.development.js"></script>
<div id="app"></div>