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TGC-1177 - Fix rounding issue with total parcel area on state #846

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Merged
dcapilla merged 2 commits into from
Apr 29, 2026
Merged

TGC-1177 - Fix rounding issue with total parcel area on state #846

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bb79ca5
TGC-1177 - Fix rounding issue with total parcel area on state
dcapilla Apr 29, 2026
c58af8a
TGC-1177 - Fix rounding issue with total parcel area on state
dcapilla Apr 29, 2026
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5 changes: 3 additions & 2 deletions ...rver/land-grants/common/common-select-parcel/common-select-land-parcel-page.controller.js
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Original file line number Diff line number Diff line change
Expand Up @@ -177,11 +177,12 @@ export default class CommonSelectLandParcelPageController extends LandGrantsQues
const landParcelMetadata = selectedParcelIds.map((id) => {
const parcel = parcelMap.get(id)
const rawArea = parcel?.area?.value
return { parcelId: id, areaHa: rawArea == null ? null : Number(rawArea) }
const areaHa = rawArea == null ? null : (Number(rawArea) * 10000) / 10000
return { parcelId: id, areaHa }
})

const totalHectaresForSelectedParcels =
Math.round(landParcelMetadata.reduce((sum, { areaHa }) => sum + (areaHa ?? 0), 0) * 10000) / 10000
(landParcelMetadata.reduce((sum, { areaHa }) => sum + (areaHa ?? 0), 0) * 10000) / 10000

if (this.minimumAreaHa !== null && totalHectaresForSelectedParcels < this.minimumAreaHa) {
const parcels = mapParcelsToViewModel(fetchedParcels)
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7 changes: 4 additions & 3 deletions ...land-grants/common/common-select-parcel/common-select-land-parcel-page.controller.test.js
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Expand Up @@ -244,7 +244,7 @@ describe('CommonSelectLandParcelPageController', () => {
expect(controller.setState).not.toHaveBeenCalled()
})

it('rounds totalHectaresForSelectedParcels to 4dp to avoid float precision issues', async () => {
it('passes parcel area sum to GAS', async () => {
fetchParcels.mockResolvedValue([
{ sheetId: 'S1', parcelId: 'P1', area: { value: 25.3874 } },
{ sheetId: 'S2', parcelId: 'P2', area: { value: 169.8586 } }
Expand All @@ -260,12 +260,13 @@ describe('CommonSelectLandParcelPageController', () => {

await controller.handlePost(request, context, h)

const expectedTotal = 25.3874 + 169.8586
expect(controller.mergeState).toHaveBeenCalledWith(
request,
context.state,
expect.objectContaining({
totalHectaresForSelectedParcels: 195.246,
additionalAnswers: { totalHectaresForSelectedParcels: 195.246 }
totalHectaresForSelectedParcels: expectedTotal,
additionalAnswers: { totalHectaresForSelectedParcels: expectedTotal }
})
)
})
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5 changes: 2 additions & 3 deletions src/server/woodland/woodland-hectares-page.controller.js
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Expand Up @@ -13,10 +13,9 @@ const HECTARES_OVER_TEN_FIELD_NAME = 'hectaresTenOrOverYearsOld'
const HECTARES_UNDER_TEN_FIELD_NAME = 'hectaresUnderTenYearsOld'

const ERROR_BELOW_MINIMUM = `The total area of woodland must be at least ${MIN_WOODLAND_TOTAL_AREA_HA}ha`
const truncate4dp = (/** @type {number} */ n) => Math.floor(n * 10000) / 10000

const errorExceedsMax = (/** @type {number} */ max) =>
`Total area of woodland cannot be more than total area of selected land parcels (${truncate4dp(max)}ha)`
`Total area of woodland cannot be more than total area of selected land parcels (${max}ha)`

/**
* @param {string} fieldName
Expand Down Expand Up @@ -53,7 +52,7 @@ export default class WoodlandHectaresPageController extends TaskPageController {

getViewModel(request, context) {
const { state } = context
const totalHectaresForSelectedParcels = truncate4dp(Number(state['totalHectaresForSelectedParcels'] ?? 0))
const totalHectaresForSelectedParcels = Number(state['totalHectaresForSelectedParcels'] ?? 0)
const viewModel = /** @type {Record<string, any>} */ (super.getViewModel(request, context))

const guidanceIndex = viewModel.components?.findIndex(
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