What is the difference between .addCase() and .addMatcher()

Question

I was using redux toolkit. What got me confused in CreateReducer is that I can't quite understand the difference between .addCase and .addMatcher?

Answer 1

• addCase will run the reducer if the dispatched action's action.type field exactly matches the string that you provide
• addMatcher will run the reducer if the callback function you provide returns true, and it's up to you to decide how the matching behavior works. Typically this is done by looking to see if the action.type field is a partial match, such as return action.type.endsWith("/pending")

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Simple Example containing both addCase and addMatcher along with addDefaultCase to conclude:

import { createAction, createReducer } from '@reduxjs/toolkit'

const increment = createAction('counter/increment')
const initialState = { value: 0 }

const counterReducer = createReducer(initialState, (builder) => {
  builder
    .addCase(increment, (state, action) => {
      // Handle increment action here...
      state.value++
    })
    .addMatcher((action) => {
      return action.type.endsWith("rejected");
    }, (state, action)=>{
      // Handle actions whose names end with "rejected" here...
    })
    .addDefaultCase((state, action)=>{
      // Handle default cases here...
    })
})