[TypeError: undefined is not an object (evaluating 'iter[Symbol.iterator]')] react-native

Question

I am using react-redux and redux-persist in my react-native project it is working fine but when i tried to add object into redux state it is throwing this error

[TypeError: undefined is not an object (evaluating 'iter[Symbol.iterator]')]

My code inside reducer is

        case ADD_FILES_DURATION:
        console.log("data received",action.data);
        return {
            ...state,
            filesDuration: [...state.filesDuration, action.data]
        };

and my state initial values are

const initialState = {
trackSpeed: "1",
filesDuration: [],
}

and from my homescreen i am trying to insert data into redux like this

    const item = {
        folderName: folderName,
        track: trackName,
        duration: duration
    }
    addFileDuration(item);

it is working fine for other redux operation but whenever i am trying to run this it is giving above error

Please help if anyone knows how to resolve this or any suggestions ?

Answer 1

After work around , i found what i was doing wrong

i was wrongly inserting data into redux that's the reason i was getting this error

So instead of this

   const item = {
    folderName: folderName,
    track: trackName,
    duration: duration
}
addFileDuration(item);

i used this

   const item = {
    "folderName": folderName,
    "track": trackName,
    "duration": duration
}
addFileDuration(item);

now it is working fine hope it may help anybody