devhub/src/selectors/shared.js

import _ from 'lodash'
import moment from 'moment'
import { List } from 'immutable'
import { createSelectorCreator } from 'reselect'

import { shallowEqualityCheckOrDeepIfArray } from '../utils/immutable'

export const stateSelector = state => state
export const entitiesSelector = state => state.get('entities')

export function immutableMemoize(
  func,
  equalityCheck = shallowEqualityCheckOrDeepIfArray,
  numberOfArgsToMemoize = null,
) {
  let lastArgs = null
  let lastResult = null
  const isEqualToLastArg = (value, index) =>
    equalityCheck(value, lastArgs[index])

  return (...args) => {
    const slicedArgs =
      typeof numberOfArgsToMemoize === 'number'
        ? numberOfArgsToMemoize < 0
          ? args.slice(numberOfArgsToMemoize)
          : args.slice(0, numberOfArgsToMemoize)
        : args

    if (
      lastArgs === null ||
      lastArgs.length !== slicedArgs.length ||
      !slicedArgs.every(isEqualToLastArg)
    ) {
      const newResult = func(...args)

      if (!equalityCheck(newResult, lastResult)) {
        lastResult = newResult
      }
    }

    lastArgs = slicedArgs
    return lastResult
  }
}

export const getKeysFromImmutableObject = obj =>
  obj ? obj.keySeq().toList() : List()

export const createObjectKeysMemoized = () =>
  immutableMemoize(getKeysFromImmutableObject)

export const createImmutableSelectorCreator = _.memoize(numberOfArgsToMemoize =>
  createSelectorCreator(
    _.bind(
      immutableMemoize,
      null,
      _,
      shallowEqualityCheckOrDeepIfArray,
      numberOfArgsToMemoize,
    ),
  ),
)

export const createImmutableSelector = createImmutableSelectorCreator()

export function isDeletedFilter(obj) {
  if (!obj) return true

  return (
    !!obj.get('deleted_at') &&
    !(
      obj.get('updated_at') &&
      moment(obj.get('updated_at')).isAfter(obj.get('deleted_at'))
    )
  )
}

export function isArchivedFilter(obj) {
  if (!obj) return false
  if (isDeletedFilter(obj)) return false

  return (
    !!obj.get('archived_at') &&
    !(
      obj.get('updated_at') &&
      moment(obj.get('updated_at')).isAfter(obj.get('archived_at'))
    )
  )
}

export function isReadFilter(obj) {
  if (!obj) return false
  if (isDeletedFilter(obj)) return false

  // preserves the latest state between last_read_at and last_unread_at
  if (obj.get('last_read_at') && obj.get('last_unread_at')) {
    return !moment(obj.get('last_unread_at')).isAfter(obj.get('last_read_at'))
  }

  // dont do !obj.get('unread') because unread=undefined on events by default
  return obj.get('unread') === false || obj.get('unread') === null
}