Redux store is not updating when modifying element propriety of an array object

Question

I have below code

case 'COMPLETE_TODO' :
state.todos[state.todos.findIndex((obj => obj.id == action.value))].status = "COMPLETED"
return {
   ...state,
   todos: state.todos
}

I feel like an array is not taken as a modified array because just a property of one single element has been updated.

Any idea?

Thanks

Do not mutate state, make a copy of state and then perform operations on it — Code Maniac
– Code Maniac, Commented Sep 27, 2019 at 1:51

Code Maniac · Accepted Answer · 2019-09-27 01:56:45Z

2

Do not mutate state, make a copy of state and then perform operations on it

case 'COMPLETE_TODO' :   
 return {
    ...state,
    todos: state.todos.map(obj=> ({...obj, status: obj.id == action.value ? "COMPLETED" : obj.status}))
 }

map create a new array, ... spread syntax creates a shallow copy, if you object is deeper then one level, then you should do a deep clone,

For deep cloning you can use

 let deepCopy = JSON.parse(JSON.stringify(state.todos))

answered Sep 27, 2019 at 1:56

Code Maniac

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