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How to Trigger Re-renders in React

30 August 2023

How to Trigger Re-renders in React

React uses a virtual DOM to minimize the number of costly DOM operations required to update your UI. It compares component state and props to determine if an actual re-render is needed. However, there may be times when you need to manually trigger a re-render in React. In this guide, we'll explore the main ways to force a component to re-render in React.

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Using the useState Hook

The easiest way to trigger a re-render is by updating state via the useState hook. For example:

import { useState } from 'react';

function MyComponent() {
  const [count, setCount] = useState(0);

  const forceUpdate = () => {
    setCount(prevCount => prevCount + 1);
  return (
    <button onClick={forceUpdate}>Force Re-render</button> 

Calling setCount will update the state and queue a re-render. This is useful for refreshing data.

Calling forceUpdate()

Class components expose the forceUpdate() method to force a re-render. For example:

class MyComponent extends React.Component {
  constructor(props) {
    this.forceUpdateHandler = this.forceUpdateHandler.bind(this);
  forceUpdateHandler() {

  render() {
    return <button onClick={this.forceUpdateHandler}>Force Re-render</button>

This will re-render the component even if state/props haven't changed.

Updating Context from Parent

If a component consumes context, forcing an update to the context value from a parent will trigger a re-render. For example:

// Context.js

export const MyContext = React.createContext();

// Parent.js 

import { MyContext } from './Context';

function Parent() {
  const [count, setCount] = useState(0);

  return (
    <MyContext.Provider value={{count}}>
      <Child />
      <button onClick={() => setCount(c => c + 1)}>
        Update Context

// Child.js

import { MyContext } from './Context';

function Child() {
  return (<div>{useContext(MyContext)}</div>);

Updating count in Parent will propagate to Child and force Child to re-render.

Using an Effect Hook

You can use the useEffect hook to trigger a re-render imperatively. For example:

function MyComponent() {
  const [count, setCount] = useState(0);

  useEffect(() => {
    const id = setInterval(() => {
      setCount(c => c + 1); 
    }, 1000);
    return () => clearInterval(id);
  }, []);

  return <div>{count}</div>;

This will re-render every second as the interval updates state.

Calling Render Directly

You can manually call render() on a class component instance. For example:

class MyComponent extends React.Component {
  constructor(props) {
    this.state = {count: 0};

  manualRender() {
    this.setState({count: this.state.count + 1});

  render() {
    return <div>{this.state.count}</div>; 

This lets you separate the state update and re-render calls.

Memoizing Components

Wrapping a component in React.memo or useMemo will control re-rendering based on prop changes. For example:

// Only re-render if props change 
const MyComponent = React.memo(function MyComponent(props) {

// Only re-render if deps change  
const MyComponent = useMemo(() => {
  return <div>Hello</div>
}, []); 

This can prevent unnecessary re-renders.

When to Re-render

Some cases where you may need to force a re-render include:

  • Refreshing data from an API
  • Resetting component state
  • Animating based on imperative commands
  • Debugging update issues

Avoid re-rendering too frequently as it impacts performance. Only re-render when necessary.


Some drawbacks of forcing re-renders:

  • Can harm optimization from virtual DOM checking
  • Can cause unnecessary UI thrashing
  • Bypasses lifecycle methods like shouldComponentUpdate
  • Triggers effects unconditionally

Use judiciously and measure the performance impact.


In summary, the main ways to trigger re-renders are:

  • Updating state with useState
  • Calling forceUpdate() in class components
  • Changing context from a parent component
  • Side effects with useEffect
  • Direct render() calls in classes

Re-rendering should be avoided when possible, but is sometimes useful. Just take care to measure performance impact.

Other Resources

For more on re-rendering in React, see:

Hopefully this guide gives you some ideas on how to think about re-renders in React apps and how to trigger them when needed.

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About the author: Daniel West
Tech Blogger & Researcher for JBI Training

+44 (0)20 8446 7555

[email protected]



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