What is the motivation for adding a reducer?
What are actions in the context of a reducer? How are they different than setting state directly?
In the context of a reducer, actions are objects that contain information about what happened and what needs to change. They typically have a type property that indicates the type of action to be performed, and other properties to carry any additional information required for the update.
This approach is different from setting state directly because actions provide a clear, predictable way of describing state changes. Rather than directly mutating state, you’re dispatching actions that describe the mutation, which are then handled by the reducer function.
What common list operation is useReduce named for, and why?
useReducer is named after the reduce method available on JavaScript arrays. The reduce method takes a list (array) and reduces it down to a single value by applying a function (the reducer) to each element of the array. Similarly, useReducer takes a series of actions (analogous to the array) and a reducer function and applies the reducer to each action to produce a single state value.When should you switch from useState to useReducer?
It’s often beneficial to switch to useReducer when the state logic becomes complex, when you have multiple sub-values to handle, or when the next state depends on the previous one.
It’s also useful when you need to pass down the state-updating function deep into the component hierarchy, as dispatching actions with useReducer can make the code easier to understand and maintain than callbacks to setState.