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alexmarqs merged 2 commits into from
Mar 2, 2026
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chore: enhance pricing calculations to support before discount amount subtotal #260

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63b3c1a
chore: enhance pricing calculations to support before discount amount…
alexmarqs Mar 2, 2026
9d0287d
chore: update @epilot/pricing-client to version 3.53.4 in package.jso…
alexmarqs Mar 2, 2026
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2 changes: 1 addition & 1 deletion package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,7 @@
},
"devDependencies": {
"@epilot/eslint-config": "^3.0.5",
"@epilot/pricing-client": "^3.51.0",
"@epilot/pricing-client": "^3.53.4",
"@types/dinero.js": "^1.9.4",
"@vitest/coverage-v8": "^1.6.1",
"concurrently": "^9.1.2",
Expand Down
10 changes: 5 additions & 5 deletions pnpm-lock.yaml
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68 changes: 68 additions & 0 deletions src/__tests__/fixtures/pricing.results.ts
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196 changes: 195 additions & 1 deletion src/computations/apply-discounts.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ import type { Currency } from 'dinero.js';
import { describe, expect, it } from 'vitest';
import { priceItem1 } from '../__tests__/fixtures/price.samples';
import { compositePriceItemWithTieredGraduatedComponent } from '../__tests__/fixtures/price.samples';
import { tax19percent } from '../__tests__/fixtures/tax.samples';
import { tax10percent, tax19percent } from '../__tests__/fixtures/tax.samples';
import {
fixedCashbackCoupon,
fixedDiscountCoupon,
Expand Down Expand Up @@ -49,6 +49,8 @@ describe('applyDiscounts', () => {
expect(result.amount_tax).toBe(94536176470571); // 789.46 * 0.75 - ((789.46 * 0.75) / 1.19)
expect(result.discount_amount).toBe(197365000000000); // 789.46 * 0.25
expect(result.discount_percentage).toBe(25);
expect(result.before_discount_amount_total).toBe(789460000000000); // original gross
expect(result.before_discount_amount_subtotal).toBe(663411764705900); // original net
});

it('should apply 50% discount correctly', () => {
Expand All @@ -75,6 +77,8 @@ describe('applyDiscounts', () => {
expect(result.amount_tax).toBe(63024117647041); // 789.46 * 0.5 - ((789.46 * 0.5) / 1.19)
expect(result.discount_amount).toBe(394730000000000); // 789.46 * 0.5
expect(result.discount_percentage).toBe(50);
expect(result.before_discount_amount_total).toBe(789460000000000); // original gross
expect(result.before_discount_amount_subtotal).toBe(663411764705900); // original net
});
});

Expand Down Expand Up @@ -102,6 +106,8 @@ describe('applyDiscounts', () => {
expect(result.amount_total).toBe(784460000000000); // 789.46 - 5.00
expect(result.amount_tax).toBe(125249915966369); // (789.46 - 5.00) - ((789.46 - 5.00) / 1.19)
expect(result.discount_amount).toBe(5000000000000); // 5.00
expect(result.before_discount_amount_total).toBe(789460000000000); // original gross
expect(result.before_discount_amount_subtotal).toBe(663411764705900); // original net
});

it('should not apply discount larger than the price', () => {
Expand All @@ -123,6 +129,8 @@ describe('applyDiscounts', () => {
expect(result.unit_amount).toBe(0);
expect(result.amount_total).toBe(0);
expect(result.unit_discount_amount).toBe(789460000000000);
expect(result.before_discount_amount_total).toBe(789460000000000); // original gross
expect(result.before_discount_amount_subtotal).toBe(663411764705900); // original net
});
});

Expand Down Expand Up @@ -248,6 +256,192 @@ describe('applyDiscounts', () => {
expect(result.amount_total).toBe(35325000000000000); // Weighted average of discounted tiers
expect(result.amount_tax).toBe(5640126050420300); // Weighted average of discounted tiers
expect(result.discount_percentage).toBe(10);
expect(result.before_discount_amount_total).toBe(39250000000000000); // sum of tier gross * qty
expect(result.before_discount_amount_subtotal).toBe(32983193277310650); // sum of tier net * qty
});
});

describe('tax-exclusive percentage discounts', () => {
const taxExclusiveParams = {
...baseParams,
isTaxInclusive: false,
priceItem: {
...priceItem1,
is_tax_inclusive: false,
_price: { ...priceItem1._price!, is_tax_inclusive: false },
},
};

// Tax-exclusive: net=100, gross=119 (19% tax), qty=1
const taxExclusiveValues = {
unit_amount: 100000000000000, // 100.00 (net is the base in tax-exclusive)
unit_amount_net: 100000000000000, // 100.00
unit_amount_gross: 119000000000000, // 119.00
amount_subtotal: 100000000000000, // 100.00
amount_total: 119000000000000, // 119.00
amount_tax: 19000000000000, // 19.00
};

it('should apply 25% percentage discount correctly (tax-exclusive)', () => {
const result = applyDiscounts(taxExclusiveValues, {
...taxExclusiveParams,
coupon: percentageDiscountCoupon,
});

// Tax-exclusive: discount is applied to net first
// unitDiscountAmountNet = 100 * 25/100 = 25
// unitDiscountAmount = 25 * 1.19 = 29.75
// afterDiscountNet = 100 - 25 = 75
// afterDiscountGross = 75 * 1.19 = 89.25
expect(result.unit_amount).toBe(75000000000000); // net after discount
expect(result.unit_amount_net).toBe(75000000000000); // 75.00
expect(result.unit_amount_gross).toBe(89250000000000); // 89.25
expect(result.amount_subtotal).toBe(75000000000000);
expect(result.amount_total).toBe(89250000000000);
expect(result.discount_percentage).toBe(25);
expect(result.before_discount_amount_total).toBe(119000000000000); // original gross
expect(result.before_discount_amount_subtotal).toBe(100000000000000); // original net
});

it('should apply fixed 5 EUR discount correctly (tax-exclusive)', () => {
const result = applyDiscounts(taxExclusiveValues, {
...taxExclusiveParams,
coupon: fixedDiscountCoupon,
});

// Tax-exclusive: fixed discount applied to net
// unitDiscountAmountNet = min(5, 100) = 5
// unitDiscountAmount = 5 * 1.19 = 5.95
// afterDiscountNet = 100 - 5 = 95
// afterDiscountGross = 95 * 1.19 = 113.05
expect(result.unit_amount).toBe(95000000000000); // net after discount
expect(result.unit_amount_net).toBe(95000000000000); // 95.00
expect(result.unit_amount_gross).toBe(113050000000000); // 113.05
expect(result.amount_subtotal).toBe(95000000000000);
expect(result.amount_total).toBe(113050000000000);
expect(result.before_discount_amount_total).toBe(119000000000000); // original gross
expect(result.before_discount_amount_subtotal).toBe(100000000000000); // original net
});
});

describe('tax-exclusive with multiplier', () => {
const taxExclusiveParams = {
...baseParams,
isTaxInclusive: false,
unitAmountMultiplier: 3,
priceItem: {
...priceItem1,
is_tax_inclusive: false,
_price: { ...priceItem1._price!, is_tax_inclusive: false },
},
};

// Tax-exclusive: net=100, gross=119 (19% tax)
const taxExclusiveValues = {
unit_amount: 100000000000000,
unit_amount_net: 100000000000000,
unit_amount_gross: 119000000000000,
amount_subtotal: 300000000000000, // 100 * 3
amount_total: 357000000000000, // 119 * 3
amount_tax: 57000000000000, // 19 * 3
};

it('should apply 25% discount with multiplier=3 (tax-exclusive)', () => {
const result = applyDiscounts(taxExclusiveValues, {
...taxExclusiveParams,
coupon: percentageDiscountCoupon,
});

// unitDiscountAmountNet = 100 * 25/100 = 25
// afterDiscountNet = 75, afterDiscountGross = 89.25
// amounts multiplied by 3
expect(result.unit_amount_net).toBe(75000000000000); // 75.00
expect(result.unit_amount_gross).toBe(89250000000000); // 89.25
expect(result.amount_subtotal).toBe(225000000000000); // 75 * 3
expect(result.amount_total).toBe(267750000000000); // 89.25 * 3
expect(result.before_discount_amount_total).toBe(357000000000000); // 119 * 3
expect(result.before_discount_amount_subtotal).toBe(300000000000000); // 100 * 3
});
});

describe('tax-inclusive with multiplier', () => {
it('should apply 25% discount with multiplier=3 (tax-inclusive)', () => {
const result = applyDiscounts(
{
unit_amount: 789460000000000,
unit_amount_net: 663411764705900,
unit_amount_gross: 789460000000000,
amount_subtotal: 1990235294117700, // 663.41 * 3
amount_total: 2368380000000000, // 789.46 * 3
amount_tax: 378144705882300, // 126.05 * 3
},
{
...baseParams,
unitAmountMultiplier: 3,
coupon: percentageDiscountCoupon,
},
);

expect(result.amount_subtotal).toBe(1492676470588287); // (789.46 * 0.75 / 1.19) * 3
expect(result.amount_total).toBe(1776285000000000); // 789.46 * 0.75 * 3
expect(result.before_discount_amount_total).toBe(2368380000000000); // 789.46 * 3
expect(result.before_discount_amount_subtotal).toBe(1990235294117700); // 663.41 * 3
});
});

describe('tax-exclusive graduated tiered prices', () => {
it('should apply percentage discount to graduated tiered prices (tax-exclusive)', () => {
const result = applyDiscounts(
{
tiers_details: [
{
quantity: 100,
unit_amount: 5000,
unit_amount_decimal: '050',
unit_amount_net: 50000000000000, // 50.00 (net is base in tax-exclusive)
unit_amount_gross: 55000000000000, // 55.00 (10% tax)
amount_subtotal: 5000000000000000, // 50 * 100
amount_total: 5500000000000000, // 55 * 100
amount_tax: 500000000000000, // 5 * 100
},
{
quantity: 200,
unit_amount: 4000,
unit_amount_decimal: '040',
unit_amount_net: 40000000000000, // 40.00
unit_amount_gross: 44000000000000, // 44.00
amount_subtotal: 8000000000000000, // 40 * 200
amount_total: 8800000000000000, // 44 * 200
amount_tax: 800000000000000, // 4 * 200
},
],
unit_amount_gross: 99000000000000,
unit_amount_net: 90000000000000,
amount_subtotal: 13000000000000000, // 5000 + 8000
amount_total: 14300000000000000, // 5500 + 8800
amount_tax: 1300000000000000,
},
{
...baseParams,
tax: tax10percent,
isTaxInclusive: false,
coupon: percentage10DiscountCoupon,
priceItem: compositePriceItemWithTieredGraduatedComponent.item_components?.[0]!,
unitAmountMultiplier: 300,
},
);

if (!result.tiers_details) {
throw new Error('Expected tiers_details to be defined');
}

// 10% discount on net: tier1 net=45*100=4500, tier2 net=36*200=7200 => subtotal=11700
expect(result.amount_subtotal).toBe(11700000000000000);
// gross = net * 1.10: tier1=49.5*100=4950, tier2=39.6*200=7920 => total=12870
expect(result.amount_total).toBe(12870000000000000);
expect(result.discount_percentage).toBe(10);
expect(result.before_discount_amount_total).toBe(14300000000000000); // original gross total
expect(result.before_discount_amount_subtotal).toBe(13000000000000000); // original net total
});
});
});
32 changes: 19 additions & 13 deletions src/computations/apply-discounts.ts
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Expand Up @@ -3,7 +3,7 @@ import { toDineroFromInteger, toDinero } from '../money/to-dinero';
import { PricingModel } from '../prices/constants';
import type { PriceItemsTotals } from '../prices/types';
import { clamp } from '../shared/clamp';
import type { Currency, Dinero, PriceItemDto, Tax, Coupon, BillingPeriod } from '../shared/types';
import type { Currency, Dinero, PriceItemDto, Tax, Coupon, BillingPeriod, TierDetails } from '../shared/types';
import { getTaxValue } from '../taxes/get-tax-value';
import { normalizeTimeFrequencyFromDineroInputValue } from '../time-frequency/normalizers';

Expand Down Expand Up @@ -64,7 +64,7 @@ export const applyDiscounts = (
// Handle graduated tiered prices
if (priceItem._price?.pricing_model === PricingModel.tieredGraduated && itemValues.tiers_details) {
// Apply discount to each tier and sum up the results
const discountedTiers = itemValues.tiers_details.map((tier) => {
const discountedTiers = itemValues.tiers_details.map((tier: TierDetails) => {
const tierUnitAmountNet = toDineroFromInteger(tier.unit_amount_net!, currency);
const tierUnitAmountGross = toDineroFromInteger(tier.unit_amount_gross!, currency);

Expand Down Expand Up @@ -126,12 +126,13 @@ export const applyDiscounts = (
discount_amount: unitDiscountAmount.multiply(tier.quantity).getAmount(),
discount_amount_net: unitDiscountAmountNet.multiply(tier.quantity).getAmount(),
before_discount_amount_total: tierUnitAmountGross.multiply(tier.quantity).getAmount(),
before_discount_amount_subtotal: tierUnitAmountNet.multiply(tier.quantity).getAmount(),
};
});

// Sum up all the discounted tier values
const totals = discountedTiers.reduce(
(acc, tier) => ({
(acc: PriceItemsTotals, tier: PriceItemsTotals) => ({
unit_amount_gross: toDineroFromInteger(acc.unit_amount_gross!)
.add(toDineroFromInteger(tier.unit_amount_gross!))
.getAmount(),
Expand All @@ -144,34 +145,37 @@ export const applyDiscounts = (
amount_total: toDineroFromInteger(acc.amount_total).add(toDineroFromInteger(tier.amount_total)).getAmount(),
amount_tax: toDineroFromInteger(acc.amount_tax).add(toDineroFromInteger(tier.amount_tax)).getAmount(),
unit_discount_amount: toDineroFromInteger(acc.unit_discount_amount || 0)
.add(toDineroFromInteger(tier.unit_discount_amount))
.add(toDineroFromInteger(tier.unit_discount_amount!))
.getAmount(),
before_discount_unit_amount: toDineroFromInteger(acc.before_discount_unit_amount || 0)
.add(toDineroFromInteger(tier.before_discount_unit_amount))
.add(toDineroFromInteger(tier.before_discount_unit_amount!))
.getAmount(),
before_discount_unit_amount_gross: toDineroFromInteger(acc.before_discount_unit_amount_gross || 0)
.add(toDineroFromInteger(tier.before_discount_unit_amount_gross))
.add(toDineroFromInteger(tier.before_discount_unit_amount_gross!))
.getAmount(),
before_discount_unit_amount_net: toDineroFromInteger(acc.before_discount_unit_amount_net || 0)
.add(toDineroFromInteger(tier.before_discount_unit_amount_net))
.add(toDineroFromInteger(tier.before_discount_unit_amount_net!))
.getAmount(),
unit_discount_amount_net: toDineroFromInteger(acc.unit_discount_amount_net || 0)
.add(toDineroFromInteger(tier.unit_discount_amount_net))
.add(toDineroFromInteger(tier.unit_discount_amount_net!))
.getAmount(),
tax_discount_amount: toDineroFromInteger(acc.tax_discount_amount || 0)
.add(toDineroFromInteger(tier.tax_discount_amount))
.add(toDineroFromInteger(tier.tax_discount_amount!))
.getAmount(),
before_discount_tax_amount: toDineroFromInteger(acc.before_discount_tax_amount || 0)
.add(toDineroFromInteger(tier.before_discount_tax_amount))
.add(toDineroFromInteger(tier.before_discount_tax_amount!))
.getAmount(),
discount_amount: toDineroFromInteger(acc.discount_amount || 0)
.add(toDineroFromInteger(tier.discount_amount))
.add(toDineroFromInteger(tier.discount_amount!))
.getAmount(),
discount_amount_net: toDineroFromInteger(acc.discount_amount_net || 0)
.add(toDineroFromInteger(tier.discount_amount_net))
.add(toDineroFromInteger(tier.discount_amount_net!))
.getAmount(),
before_discount_amount_total: toDineroFromInteger(acc.before_discount_amount_total || 0)
.add(toDineroFromInteger(tier.before_discount_amount_total))
.add(toDineroFromInteger(tier.before_discount_amount_total!))
.getAmount(),
before_discount_amount_subtotal: toDineroFromInteger(acc.before_discount_amount_subtotal || 0)
.add(toDineroFromInteger(tier.before_discount_amount_subtotal!))
.getAmount(),
}),
{
Expand All @@ -190,6 +194,7 @@ export const applyDiscounts = (
discount_amount: 0,
discount_amount_net: 0,
before_discount_amount_total: 0,
before_discount_amount_subtotal: 0,
} as PriceItemsTotals,
);

Expand Down Expand Up @@ -257,5 +262,6 @@ export const applyDiscounts = (
discount_amount_net: unitDiscountAmountNet.multiply(unitAmountMultiplier).getAmount(),
...(typeof discountPercentage === 'number' && { discount_percentage: discountPercentage }),
before_discount_amount_total: unitAmountGross.multiply(unitAmountMultiplier).getAmount(),
before_discount_amount_subtotal: unitAmountNet.multiply(unitAmountMultiplier).getAmount(),
};
};
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