React Hooks and Component Lifecycle Equivalent
What are the equivalents of the componentDidMount
, componentDidUpdate
, and componentWillUnmount
lifecycle hooks using React hooks like useEffect
?
javascript reactjs react-hooks
add a comment |
What are the equivalents of the componentDidMount
, componentDidUpdate
, and componentWillUnmount
lifecycle hooks using React hooks like useEffect
?
javascript reactjs react-hooks
add a comment |
What are the equivalents of the componentDidMount
, componentDidUpdate
, and componentWillUnmount
lifecycle hooks using React hooks like useEffect
?
javascript reactjs react-hooks
What are the equivalents of the componentDidMount
, componentDidUpdate
, and componentWillUnmount
lifecycle hooks using React hooks like useEffect
?
javascript reactjs react-hooks
javascript reactjs react-hooks
asked Nov 11 at 22:49
Yangshun Tay
8,83153667
8,83153667
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
componentDidMount
Pass an empty array as the second argument to useEffect()
to run only the callback on mount only.
function ComponentDidMount() {
const [count, setCount] = React.useState(0);
React.useEffect(() => {
console.log('componentDidMount');
}, );
return (
<div>
<p>componentDidMount: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentDidMount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentDidUpdate
componentDidUpdate()
is invoked immediately after updating occurs. This method is not called for the initial render. useEffect
runs on every render including the first. So if you want to have a strict equivalent as componentDidUpdate
, you have to use useRef
to determine if the component has been mounted once. If you want to be even stricter, use useLayoutEffect()
, but it fires synchronously. In most cases, useEffect()
should be sufficient.
This answer is inspired by Tholle, all credit goes to him.
function ComponentDidUpdate() {
const [count, setCount] = React.useState(0);
const isFirstUpdate = React.useRef(true);
React.useEffect(() => {
if (isFirstUpdate.current) {
isFirstUpdate.current = false;
return;
}
console.log('componentDidUpdate');
});
return (
<div>
<p>componentDidUpdate: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<ComponentDidUpdate />,
document.getElementById("app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentWillUnmount
Return a callback in useEffect's callback argument and it will be called before unmounting.
function ComponentWillUnmount() {
function ComponentWillUnmountInner(props) {
React.useEffect(() => {
return () => {
console.log('componentWillUnmount');
};
}, );
return (
<div>
<p>componentWillUnmount</p>
</div>
);
}
const [count, setCount] = React.useState(0);
return (
<div>
{count % 2 === 0 ? (
<ComponentWillUnmountInner count={count} />
) : (
<p>No component</p>
)}
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentWillUnmount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
add a comment |
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1 Answer
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1 Answer
1
active
oldest
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oldest
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oldest
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componentDidMount
Pass an empty array as the second argument to useEffect()
to run only the callback on mount only.
function ComponentDidMount() {
const [count, setCount] = React.useState(0);
React.useEffect(() => {
console.log('componentDidMount');
}, );
return (
<div>
<p>componentDidMount: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentDidMount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentDidUpdate
componentDidUpdate()
is invoked immediately after updating occurs. This method is not called for the initial render. useEffect
runs on every render including the first. So if you want to have a strict equivalent as componentDidUpdate
, you have to use useRef
to determine if the component has been mounted once. If you want to be even stricter, use useLayoutEffect()
, but it fires synchronously. In most cases, useEffect()
should be sufficient.
This answer is inspired by Tholle, all credit goes to him.
function ComponentDidUpdate() {
const [count, setCount] = React.useState(0);
const isFirstUpdate = React.useRef(true);
React.useEffect(() => {
if (isFirstUpdate.current) {
isFirstUpdate.current = false;
return;
}
console.log('componentDidUpdate');
});
return (
<div>
<p>componentDidUpdate: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<ComponentDidUpdate />,
document.getElementById("app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentWillUnmount
Return a callback in useEffect's callback argument and it will be called before unmounting.
function ComponentWillUnmount() {
function ComponentWillUnmountInner(props) {
React.useEffect(() => {
return () => {
console.log('componentWillUnmount');
};
}, );
return (
<div>
<p>componentWillUnmount</p>
</div>
);
}
const [count, setCount] = React.useState(0);
return (
<div>
{count % 2 === 0 ? (
<ComponentWillUnmountInner count={count} />
) : (
<p>No component</p>
)}
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentWillUnmount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
add a comment |
componentDidMount
Pass an empty array as the second argument to useEffect()
to run only the callback on mount only.
function ComponentDidMount() {
const [count, setCount] = React.useState(0);
React.useEffect(() => {
console.log('componentDidMount');
}, );
return (
<div>
<p>componentDidMount: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentDidMount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentDidUpdate
componentDidUpdate()
is invoked immediately after updating occurs. This method is not called for the initial render. useEffect
runs on every render including the first. So if you want to have a strict equivalent as componentDidUpdate
, you have to use useRef
to determine if the component has been mounted once. If you want to be even stricter, use useLayoutEffect()
, but it fires synchronously. In most cases, useEffect()
should be sufficient.
This answer is inspired by Tholle, all credit goes to him.
function ComponentDidUpdate() {
const [count, setCount] = React.useState(0);
const isFirstUpdate = React.useRef(true);
React.useEffect(() => {
if (isFirstUpdate.current) {
isFirstUpdate.current = false;
return;
}
console.log('componentDidUpdate');
});
return (
<div>
<p>componentDidUpdate: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<ComponentDidUpdate />,
document.getElementById("app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentWillUnmount
Return a callback in useEffect's callback argument and it will be called before unmounting.
function ComponentWillUnmount() {
function ComponentWillUnmountInner(props) {
React.useEffect(() => {
return () => {
console.log('componentWillUnmount');
};
}, );
return (
<div>
<p>componentWillUnmount</p>
</div>
);
}
const [count, setCount] = React.useState(0);
return (
<div>
{count % 2 === 0 ? (
<ComponentWillUnmountInner count={count} />
) : (
<p>No component</p>
)}
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentWillUnmount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
add a comment |
componentDidMount
Pass an empty array as the second argument to useEffect()
to run only the callback on mount only.
function ComponentDidMount() {
const [count, setCount] = React.useState(0);
React.useEffect(() => {
console.log('componentDidMount');
}, );
return (
<div>
<p>componentDidMount: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentDidMount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentDidUpdate
componentDidUpdate()
is invoked immediately after updating occurs. This method is not called for the initial render. useEffect
runs on every render including the first. So if you want to have a strict equivalent as componentDidUpdate
, you have to use useRef
to determine if the component has been mounted once. If you want to be even stricter, use useLayoutEffect()
, but it fires synchronously. In most cases, useEffect()
should be sufficient.
This answer is inspired by Tholle, all credit goes to him.
function ComponentDidUpdate() {
const [count, setCount] = React.useState(0);
const isFirstUpdate = React.useRef(true);
React.useEffect(() => {
if (isFirstUpdate.current) {
isFirstUpdate.current = false;
return;
}
console.log('componentDidUpdate');
});
return (
<div>
<p>componentDidUpdate: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<ComponentDidUpdate />,
document.getElementById("app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentWillUnmount
Return a callback in useEffect's callback argument and it will be called before unmounting.
function ComponentWillUnmount() {
function ComponentWillUnmountInner(props) {
React.useEffect(() => {
return () => {
console.log('componentWillUnmount');
};
}, );
return (
<div>
<p>componentWillUnmount</p>
</div>
);
}
const [count, setCount] = React.useState(0);
return (
<div>
{count % 2 === 0 ? (
<ComponentWillUnmountInner count={count} />
) : (
<p>No component</p>
)}
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentWillUnmount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentDidMount
Pass an empty array as the second argument to useEffect()
to run only the callback on mount only.
function ComponentDidMount() {
const [count, setCount] = React.useState(0);
React.useEffect(() => {
console.log('componentDidMount');
}, );
return (
<div>
<p>componentDidMount: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentDidMount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentDidUpdate
componentDidUpdate()
is invoked immediately after updating occurs. This method is not called for the initial render. useEffect
runs on every render including the first. So if you want to have a strict equivalent as componentDidUpdate
, you have to use useRef
to determine if the component has been mounted once. If you want to be even stricter, use useLayoutEffect()
, but it fires synchronously. In most cases, useEffect()
should be sufficient.
This answer is inspired by Tholle, all credit goes to him.
function ComponentDidUpdate() {
const [count, setCount] = React.useState(0);
const isFirstUpdate = React.useRef(true);
React.useEffect(() => {
if (isFirstUpdate.current) {
isFirstUpdate.current = false;
return;
}
console.log('componentDidUpdate');
});
return (
<div>
<p>componentDidUpdate: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<ComponentDidUpdate />,
document.getElementById("app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
componentWillUnmount
Return a callback in useEffect's callback argument and it will be called before unmounting.
function ComponentWillUnmount() {
function ComponentWillUnmountInner(props) {
React.useEffect(() => {
return () => {
console.log('componentWillUnmount');
};
}, );
return (
<div>
<p>componentWillUnmount</p>
</div>
);
}
const [count, setCount] = React.useState(0);
return (
<div>
{count % 2 === 0 ? (
<ComponentWillUnmountInner count={count} />
) : (
<p>No component</p>
)}
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentWillUnmount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
function ComponentDidMount() {
const [count, setCount] = React.useState(0);
React.useEffect(() => {
console.log('componentDidMount');
}, );
return (
<div>
<p>componentDidMount: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentDidMount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
function ComponentDidMount() {
const [count, setCount] = React.useState(0);
React.useEffect(() => {
console.log('componentDidMount');
}, );
return (
<div>
<p>componentDidMount: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentDidMount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
function ComponentDidUpdate() {
const [count, setCount] = React.useState(0);
const isFirstUpdate = React.useRef(true);
React.useEffect(() => {
if (isFirstUpdate.current) {
isFirstUpdate.current = false;
return;
}
console.log('componentDidUpdate');
});
return (
<div>
<p>componentDidUpdate: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<ComponentDidUpdate />,
document.getElementById("app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
function ComponentDidUpdate() {
const [count, setCount] = React.useState(0);
const isFirstUpdate = React.useRef(true);
React.useEffect(() => {
if (isFirstUpdate.current) {
isFirstUpdate.current = false;
return;
}
console.log('componentDidUpdate');
});
return (
<div>
<p>componentDidUpdate: {count} times</p>
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<ComponentDidUpdate />,
document.getElementById("app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
function ComponentWillUnmount() {
function ComponentWillUnmountInner(props) {
React.useEffect(() => {
return () => {
console.log('componentWillUnmount');
};
}, );
return (
<div>
<p>componentWillUnmount</p>
</div>
);
}
const [count, setCount] = React.useState(0);
return (
<div>
{count % 2 === 0 ? (
<ComponentWillUnmountInner count={count} />
) : (
<p>No component</p>
)}
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentWillUnmount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
function ComponentWillUnmount() {
function ComponentWillUnmountInner(props) {
React.useEffect(() => {
return () => {
console.log('componentWillUnmount');
};
}, );
return (
<div>
<p>componentWillUnmount</p>
</div>
);
}
const [count, setCount] = React.useState(0);
return (
<div>
{count % 2 === 0 ? (
<ComponentWillUnmountInner count={count} />
) : (
<p>No component</p>
)}
<button
onClick={() => {
setCount(count + 1);
}}
>
Click Me
</button>
</div>
);
}
ReactDOM.render(
<div>
<ComponentWillUnmount />
</div>,
document.querySelector("#app")
);
<script src="https://unpkg.com/react@16.7.0-alpha.0/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16.7.0-alpha.0/umd/react-dom.development.js"></script>
<div id="app"></div>
edited Nov 11 at 23:08
answered Nov 11 at 22:49
Yangshun Tay
8,83153667
8,83153667
add a comment |
add a comment |
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StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53254017%2freact-hooks-and-component-lifecycle-equivalent%23new-answer', 'question_page');
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StackExchange.helpers.onClickDraftSave('#login-link');
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StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
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