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export const SET_FILTER = 'LIST_SET_FILTER'
export const SET_SORT = 'LIST_SET_SORT'
export const ADD = 'LIST_ADD'
export const UPDATE = 'LIST_UPDATE'
export const REMOVE = 'LIST_REMOVE'
export const RECEIVE = 'LIST_RECEIVE'
const defaultState = {
byId: {},
list: [],
listIndex: {},
view: [],
viewIndex: {},
}
/**
* The store reducer can be used as a mixin to another reducer that always returns a
* new { byId, list, listIndex, view, viewIndex } object. The reducer using the store
* usually has to map its action to the matching store action and then call the mixin with that.
*
* Example Usage:
*
* import reduceStore, * as storeActions from "./utils/store"
*
* case EVENTLOG_ADD:
* return {
* ...state,
* ...reduceStore(state, storeActions.add(action.data))
* }
*
*/
export default function reduce(state = defaultState, action) {
let { byId, list, listIndex, view, viewIndex } = state
switch (action.type) {
case SET_FILTER:
view = list.filter(action.filter).sort(action.sort)
viewIndex = {}
view.forEach((item, index) => {
viewIndex[item.id] = index
})
break
case SET_SORT:
view = [...view].sort(action.sort)
viewIndex = {}
view.forEach((item, index) => {
viewIndex[item.id] = index
})
break
case ADD:
if (action.item.id in byId) {
// we already had that.
break
}
byId = { ...byId, [action.item.id]: action.item }
listIndex = { ...listIndex, [action.item.id]: list.length }
list = [...list, action.item]
if (action.filter(action.item)) {
({ view, viewIndex } = sortedInsert(state, action.item, action.sort))
}
break
case UPDATE:
byId = { ...byId, [action.item.id]: action.item }
list = [...list]
list[listIndex[action.item.id]] = action.item
let hasOldItem = action.item.id in viewIndex
let hasNewItem = action.filter(action.item)
if (hasNewItem && !hasOldItem) {
({view, viewIndex} = sortedInsert(state, action.item, action.sort))
}
else if (!hasNewItem && hasOldItem) {
({data: view, dataIndex: viewIndex} = removeData(view, viewIndex, action.item.id))
}
else if (hasNewItem && hasOldItem) {
({view, viewIndex} = sortedUpdate(state, action.item, action.sort))
}
break
case REMOVE:
if (!(action.id in byId)) {
break
}
byId = {...byId}
delete byId[action.id];
({data: list, dataIndex: listIndex} = removeData(list, listIndex, action.id))
if (action.id in viewIndex) {
({data: view, dataIndex: viewIndex} = removeData(view, viewIndex, action.id))
}
break
case RECEIVE:
list = action.list
listIndex = {}
byId = {}
list.forEach((item, i) => {
byId[item.id] = item
listIndex[item.id] = i
})
view = list.filter(action.filter).sort(action.sort)
viewIndex = {}
view.forEach((item, index) => {
viewIndex[item.id] = index
})
break
}
return { byId, list, listIndex, view, viewIndex }
}
export function setFilter(filter = defaultFilter, sort = defaultSort) {
return { type: SET_FILTER, filter, sort }
}
export function setSort(sort = defaultSort) {
return { type: SET_SORT, sort }
}
export function add(item, filter = defaultFilter, sort = defaultSort) {
return { type: ADD, item, filter, sort }
}
export function update(item, filter = defaultFilter, sort = defaultSort) {
return { type: UPDATE, item, filter, sort }
}
export function remove(id) {
return { type: REMOVE, id }
}
export function receive(list, filter = defaultFilter, sort = defaultSort) {
return { type: RECEIVE, list, filter, sort }
}
function sortedInsert(state, item, sort) {
const index = sortedIndex(state.view, item, sort)
const view = [...state.view]
const viewIndex = { ...state.viewIndex }
view.splice(index, 0, item)
for (let i = view.length - 1; i >= index; i--) {
viewIndex[view[i].id] = i
}
return { view, viewIndex }
}
function removeData(currentData, currentDataIndex, id) {
const index = currentDataIndex[id]
const data = [...currentData]
const dataIndex = { ...currentDataIndex }
delete dataIndex[id];
data.splice(index, 1)
for (let i = data.length - 1; i >= index; i--) {
dataIndex[data[i].id] = i
}
return { data, dataIndex }
}
function sortedUpdate(state, item, sort) {
let view = [...state.view]
let viewIndex = { ...state.viewIndex }
let index = viewIndex[item.id]
view[index] = item
while (index + 1 < view.length && sort(view[index], view[index + 1]) > 0) {
view[index] = view[index + 1]
view[index + 1] = item
viewIndex[item.id] = index + 1
viewIndex[view[index].id] = index
++index
}
while (index > 0 && sort(view[index], view[index - 1]) < 0) {
view[index] = view[index - 1]
view[index - 1] = item
viewIndex[item.id] = index - 1
viewIndex[view[index].id] = index
--index
}
return { view, viewIndex }
}
function sortedIndex(list, item, sort) {
let low = 0
let high = list.length
while (low < high) {
const middle = (low + high) >>> 1
if (sort(item, list[middle]) >= 0) {
low = middle + 1
} else {
high = middle
}
}
return low
}
function defaultFilter() {
return true
}
function defaultSort(a, b) {
return 0
}
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