---
title: Higher-Order Components
---
## Higher-Order Components
In React, a **Higher-Order Component** (HOC) is a function that takes a component and returns a new component. Programmers use HOCs to achieve **component logic reuse**.
If you've used Redux's `connect`, you've already worked with Higher-Order Components.
The core idea is:
```jsx
const EnhancedComponent = enhance(WrappedComponent);
```
Where:
* `enhance` is the Higher-Order Component;
* `WrappedComponent` is the component you want to enhance; and
* `EnhancedComponent` is the new component created.
This could be the body of the `enhance` HOC:
```jsx
function enhance(WrappedComponent) {
return class extends React.Component {
render() {
const extraProp = 'This is an injected prop!';
return (
);
}
}
}
```
In this case, `enhance` returns an **anonymous class** that extends `React.Component`. This new component is doing three simple things:
* Rendering the `WrappedComponent` within a `div` element
* Passing its own props to the `WrappedComponent`
* Injecting an extra prop to the `WrappedComponent`
### Caveats
Higher-order components come with a few caveats that aren’t immediately obvious if you’re new to React.
#### Refs Aren't Passed Through
While the convention for higher-order components is to pass through all props to the wrapped component, this does not work for refs. That’s because `ref` is not really a prop — like `key`, it’s handled specially by React. If you add a ref to an element whose component is the result of a HOC, the ref refers to an instance of the outermost container component, not the wrapped component.
The solution for this problem is to use the React.forwardRef API (introduced with React 16.3)
```jsx
function enhance(WrappedComponent) {
const wrapper = React.createRef((props,ref) => {
return(
)
})
}
```
## Other Resources
* [React docs: Higher-Order Components](https://reactjs.org/docs/higher-order-components.html)
* [React docs: Forwarding Refs](https://reactjs.org/docs/forwarding-refs.html)