
React and React Native
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The next life cycle method you're going to learn about is used to implement heuristics that improve component rendering performance. You'll see that if the state of a component hasn't changed, then there's no need to render. Then, you'll implement a component that uses specific metadata from the API to determine whether or not the component needs to be re-rendered.
The shouldComponentUpdate()
life cycle method is used to determine whether or not the component will render when asked to. For example, if this method were implemented and returned false
, the entire life cycle of the component would short-circuit, and no render would happen. This can be an important check to have in place if the component is rendering a lot of data and is re-rendered frequently. The trick is knowing whether or not the component state has changed.
Let's take a look at a simple list component:
function referenceEquality...