render-callback.md

id	sidebar_label	title	description	keywords	version	image
render-callback	Render callback	Render Callback	Render callback | React Patterns, techniques, tips and tricks in development for React developers.	render callback reactpatterns react patterns reactjspatterns reactjs patterns react reactjs react techniques react tips and tricks	Render callback	/img/reactpatterns-cover.png

For example below, notice that we create a function foo which takes a callback function as a parameter. When we call foo, it turns around and calls back to the passed-in function.

const foo = (hello) => {
  return hello('foo')
}

foo((name) => {
  return `hello from ${name}`
})

// hello from foo

As you can see, foo used the callback function to complete a portion of a string.

In the React world, a render callback works the same way, but returning a portion of the rendered markup.