Como posso melhorar esse código javascript encapsulado e usando método imutável?

Eu tenho esse código, mas preciso retornar funções puras em vez de funções mutáveis.

É possível? Talvez usando OOP? Não sei como melhorar isso.

Tentei retornar os valores de cada função, mas não obtive sucesso.

import { AssetStatusType } from '@domain/interfaces/common'

import {
BothComponentType,
ComponentsType,
GroupFiltersType,
OperationType,
OverviewModelType,
PendenciesOverviewType,
PendenciesType,
StructurePendenciesCount,
StructureStatusCount
} from '../../types'

const updateStatusCount = (
 statusCount: StructureStatusCount,
 status: AssetStatusType
) => {
 statusCount[status] = (statusCount[status] || 0) + 1
}

const updatePendenciesCount = (
 pendenciesCount: StructurePendenciesCount,
 key: AssetStatusType,
 subKey: OperationType | PendenciesOverviewType
) => {
 pendenciesCount[key] = pendenciesCount[key] ?? {}
 pendenciesCount[key][subKey] = (pendenciesCount[key]?.[subKey] || 0) + 1
}

const processOverviewPendencies = (
 pendencies: PendenciesType[] | null | undefined,
 pendenciesCount: StructurePendenciesCount,
 countedIds: Set<string>,
 id: string
) => {
 if (pendencies?.length) {
 for (const { state, pendencyType } of pendencies) {
 const uniqueId = `${state}-${pendencyType}-${id}`
 if (!countedIds.has(uniqueId)) {
 updatePendenciesCount(pendenciesCount, state, pendencyType)

 countedIds.add(uniqueId)
 }
 }
 }
}

const processOverviewComponents = (
 components: ComponentsType[],
 isGroupByTree: boolean,
 statusCount: StructureStatusCount,
 pendenciesCount: StructurePendenciesCount,
 countedIds: Set<string>,
 id: string,
 type: BothComponentType
) => {
 for (const { pendencies, status, operationType } of components) {
 if (isGroupByTree && type === 'location') {
 updateStatusCount(statusCount, status)

 if (operationType) {
 updatePendenciesCount(pendenciesCount, status, operationType)
 }
 }
 processOverviewPendencies(pendencies, pendenciesCount, countedIds, id)
 }
}

const processOverviewData = (
 data: OverviewModelType[],
 groupBy: GroupFiltersType,
 statusCount: StructureStatusCount,
 pendenciesCount: StructurePendenciesCount,
 countedIds: Set<string>
) => {
 const isGroupByTree = groupBy === 'tree'
 const isGroupByAsset = groupBy === 'asset'

 for (const { id, status, components, operationType, type } of data) {
 if (isGroupByAsset || type === 'asset') {
 updateStatusCount(statusCount, status)
 if (operationType) {
 updatePendenciesCount(pendenciesCount, status, operationType)
 }
 }

 processOverviewComponents(
 components,
 isGroupByTree,
 statusCount,
 pendenciesCount,
 countedIds,
 id,
 type
 )
 }
}

export const calculateOverviewCounts = (
 data: OverviewModelType[],
 groupBy: GroupFiltersType
) => {
 const statusCount: StructureStatusCount = {} as StructureStatusCount
 const pendenciesCount: StructurePendenciesCount =
 {} as StructurePendenciesCount

 const countedIds = new Set<string>()

 processOverviewData(data, groupBy, statusCount, pendenciesCount, countedIds)

 return { ...statusCount, pendencies: pendenciesCount }
}

	Existe uma maneira mais limpa e elegante de fazer isso? Preciso retornar um objeto como este:

// calculateOverviewCounts return this

{

 pendencies: StructurePendenciesCount;
 working: number;
 inAlert: number;
 warning: number;
 stopped: number;
 off: number;
}

	StructurePendenciesCount é:

	![imagem](https://forum.imasters.com.br/monthly_2023_12/image.png.6294a8704a843ef19f1128d678b5773c.png)