Pushing Data Into My Redux State

Question

Right now I am mapping over an array with an endpoint to my API. From there I am taking every link and calling a get request on each thing I map over. My issue is that I am not able to save everything into my redux state. I have tried using concat and push to take everything and put it all in one array in my redux state.

MomentContent.js:

componentDidMount () {

      this.props.photos.map(photo => {
        this.props.fetchPhoto(this.props.token, photo)}
      )
    }

index.js (actions):

export const fetchPhoto = (token, photo) => dispatch => {
  console.log('right token')
  console.log(token);
  fetch(photo, {
    method: 'GET',
    headers: {
      'Accept': 'application/json',
      'Content-Type': 'application/json',
      'Authorization': `Token ${token}`,
    }
  })
  .then(res => res.json())
  .then(parsedRes => {
    console.log('photo data')
    console.log(parsedRes)
    dispatch(getPhoto(parsedRes))
  })
}

export const getPhoto = (photo) => {
  console.log('RES')
  console.log(photo)
  return {
    type: GET_PHOTO,
    photo: photo
  }
}

When I use concat (reducer):

import {
  GET_PHOTO
} from '../actions';

const initialState = {
  photo: []
}

const photoReducer = (state = initialState, action) => {
  switch(action.type) {
    case GET_PHOTO:
      return {
        ...state,
        photo: initialState.photo.concat([action.photo])
      }

    default:
      return state;
  }
}

export default photoReducer

When I use push (reducer):

import {
  GET_PHOTO
} from '../actions';

const initialState = {
  photo: []
}

const photoReducer = (state = initialState, action) => {
  switch(action.type) {
    case GET_PHOTO:
      return {
        ...state,
        photo: initialState.photo.push([action.photo])
      }

    default:
      return state;
  }
}

export default photoReducer

UPDATE (another issue):

I was able to get it to work with :

return {
        ...state,
        photo: [...state.photo, action.photo]
      }

The issue now is that every time I refresh the same data is pushed again, so everything multiplies. Is there a way to fix this?

Answer 1

You need to merge your updatedState and not initialState to the reducer in order to update

Either using concat:

return {
  ...state,
  photo: state.photo.concat([action.photo])
}

or using spread operator

return {
  ...state,
  photo: [...state.photo, action.photo]
}

Answer 2

the push does not work correctly in redux, the ideal is to use the spread operator to concatenate the arrays

return {
     ... state,
     photo: [... initialState.photo, action.photo]
}