What is the difference between useCallback and useMemo?
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# Understanding useCallback and useMemo in React
## Introduction
In React, `useCallback` and `useMemo` are hooks that help optimize performance by memoizing functions and values. This document explores the differences between these two hooks and provides guidance on when to use each.
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## When to Use useMemo
`useMemo` is used to memoize the **result of a computation**. Imagine you have a trading platform that receives real-time data on the prices of various assets. On the frontend, you need to recalculate these values and update various charts, tables, user portfolios, etc. However, not all updates require a re-render. For example, if the price of an asset hasn’t changed, then there’s no need to redraw the chart associated with it. `Memoization (useMemo)` allows you to cache values and update the component only when the input parameters change.
## When to Use useCallback
If a component renders, the functions declared within it will also be recreated. In theory, this can impact performance, especially when using various super abstract frameworks like `Ionic`. `useCallback` allows you to return the same function between renders as long as the dependencies do not change. Thus, it memoizes the function and helps us avoid unnecessary recreations.
## Best Practices
In an interview, it’s good practice to say that any performance optimizations should be based on current or potential issues, and the worst thing you can do is spend time optimizing something that makes no sense.Short Answer
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