feat: group all-account rows by instrument and day (WealthLedger/main#47) (#126)

src/shared/lib/decimal.test.ts

@@ -0,0 +1,41 @@
+import { describe, expect, it } from "vitest";
+
+import { sumMoney } from "./decimal";
+
+describe("sumMoney", () => {
+	it("adds exact signed decimals independently per currency", () => {
+		expect(sumMoney([
+			{ currency: "RUB", value: "0.1" },
+			{ currency: "USD", value: "0.01" },
+			{ currency: "RUB", value: "0.2" },
+			{ currency: "RUB", value: "-1500000.45" },
+			{ currency: "USD", value: "-0.02" },
+			{ currency: "RUB", value: "200" },
+		])).toEqual([
+			{ currency: "RUB", value: "-1499800.15" },
+			{ currency: "USD", value: "-0.01" },
+		]);
+	});
+
+	it("preserves significant fractional digits and a compensated zero", () => {
+		expect(sumMoney([
+			{ currency: "RUB", value: "100.5" },
+			{ currency: "RUB", value: "49.50" },
+			{ currency: "RUB", value: "0.005" },
+		])).toEqual([{ currency: "RUB", value: "150.005" }]);
+		expect(sumMoney([
+			{ currency: "RUB", value: "100" },
+			{ currency: "RUB", value: "-100" },
+		])).toEqual([{ currency: "RUB", value: "0" }]);
+	});
+
+	it.each(["", ".", "1.2.3", "not-a-number"])(
+		"rejects malformed amount %s instead of treating it as zero",
+		(value) => {
+			expect(sumMoney([
+				{ currency: "RUB", value: "100" },
+				{ currency: "RUB", value },
+			])).toBeNull();
+		},
+	);
+});

src/shared/lib/decimal.ts

@@ -0,0 +1,75 @@
+type Decimal = { scale: number; value: bigint };
+
+type Money = { currency: string; value: string };
+
+const DECIMAL_PARTS = 2;
+const RADIX = 10n;
+// Decimal grammar is bounded to digits and one optional dot.
+// eslint-disable-next-line security/detect-unsafe-regex
+const decimalPattern = /^-?\d+(?:\.\d+)?$/;
+
+function decimalFromString(value: string): Decimal {
+	if (!decimalPattern.test(value)) throw new SyntaxError("Invalid decimal");
+	const [whole = "0", fraction = ""] = value.split(".", DECIMAL_PARTS);
+
+	return { scale: fraction.length, value: BigInt(`${whole}${fraction}`) };
+}
+
+function decimalToString(decimal: Decimal): string {
+	const sign = decimal.value < 0n ? "-" : "";
+
+	const digits = (decimal.value < 0n ? -decimal.value : decimal.value)
+		.toString()
+		.padStart(decimal.scale + 1, "0");
+
+	const whole = decimal.scale
+		? digits.slice(0, -decimal.scale)
+		: digits;
+
+	let fraction = decimal.scale ? digits.slice(-decimal.scale) : "";
+
+	while (fraction.endsWith("0")) fraction = fraction.slice(0, -1);
+	const suffix = fraction ? `.${fraction}` : "";
+
+	return `${sign}${whole}${suffix}`;
+}
+
+function sumDecimals(decimals: readonly Decimal[]): Decimal {
+	const scale = Math.max(...decimals.map(decimal => decimal.scale));
+
+	const value = decimals.reduce(
+		(sum, decimal) =>
+			sum + decimal.value * RADIX ** BigInt(scale - decimal.scale),
+		0n,
+	);
+
+	return { scale, value };
+}
+
+function sumMoney(amounts: readonly Money[]): Money[] | null {
+	const decimals = new Map<string, Decimal[]>();
+
+	for (const amount of amounts) {
+		try {
+			const values = decimals.get(amount.currency) ?? [];
+			values.push(decimalFromString(amount.value));
+			decimals.set(amount.currency, values);
+		}
+		catch {
+			return null;
+		}
+	}
+
+	return Array.from(decimals, ([currency, values]) => ({
+		currency,
+		value: decimalToString(sumDecimals(values)),
+	}));
+}
+
+export {
+	type Decimal,
+	decimalFromString,
+	decimalToString,
+	sumDecimals,
+	sumMoney,
+};

src/shared/lib/display.test.ts

@@ -3,6 +3,7 @@ import { describe, expect, it } from "vitest";
 import {
 	formatDate,
 	formatMoney,
+	formatSnapshotDay,
 	formatSnapshotTime,
 	instrumentLogoUrl,
 } from "./display";
@@ -22,6 +23,10 @@ describe("shared display helpers", () => {
 		}).format(new Date(instant));
 
 		expect(formatSnapshotTime(instant)).toBe(expected);
+		expect(formatSnapshotDay(instant)).toBe(
+			new Intl.DateTimeFormat("ru-RU", { dateStyle: "short" })
+				.format(new Date(instant)),
+		);
 	});
 	it("formats decimal strings without financial arithmetic", () => {
 		expect(formatMoney({ currency: "RUB", value: "-1234567.89" })).toBe(

src/shared/lib/display.ts

@@ -135,6 +135,14 @@ const snapshotFormatter = new Intl.DateTimeFormat("ru-RU", {
 	timeStyle: "short",
 });
 
+const snapshotDayFormatter = new Intl.DateTimeFormat("ru-RU", {
+	dateStyle: "short",
+});
+
+function formatSnapshotDay(value: string): string {
+	return snapshotDayFormatter.format(new Date(value));
+}
+
 function formatSnapshotTime(value: string): string {
 	return snapshotFormatter.format(new Date(value));
 }
@@ -160,6 +168,7 @@ export {
 	formatDate,
 	formatDecimal,
 	formatMoney,
+	formatSnapshotDay,
 	formatSnapshotTime,
 	instrumentLogoUrl,
 	portfolioCategoryPresentation,

src/shared/lib/group-items.test.ts

@@ -0,0 +1,45 @@
+import { describe, expect, it } from "vitest";
+
+import { groupItems } from "./group-items";
+
+describe("groupItems", () => {
+	it("keeps the first key position and source order through interleaving", () => {
+		const a1 = { id: "A1", key: "A" };
+		const b = { id: "B", key: null };
+		const a2 = { id: "A2", key: "A" };
+		const c = { id: "C", key: "C" };
+		const a3 = { id: "A3", key: "A" };
+		const input = [a1, b, a2, c, a3];
+
+		const result = groupItems(input, item => item.key);
+
+		expect(result).toEqual([
+			{ items: [a1, a2, a3], key: "A", type: "group" },
+			{ item: b, type: "single" },
+			{ item: c, type: "single" },
+		]);
+		expect(input.map(item => item.id)).toEqual(["A1", "B", "A2", "C", "A3"]);
+	});
+
+	it("keeps two interleaved groups independent and singleton rows single", () => {
+		const result = groupItems(
+			[
+				{ id: "X1", key: "X" },
+				{ id: "Y1", key: "Y" },
+				{ id: "X2", key: "X" },
+				{ id: "Y2", key: "Y" },
+				{ id: "X3", key: "X" },
+				{ id: "Z1", key: "Z" },
+			],
+			item => item.key,
+		);
+
+		expect(result.map(entry => entry.type === "group"
+			? [entry.key, entry.items.map(item => item.id)]
+			: [null, [entry.item.id]])).toEqual([
+			["X", ["X1", "X2", "X3"]],
+			["Y", ["Y1", "Y2"]],
+			[null, ["Z1"]],
+		]);
+	});
+});

src/shared/lib/group-items.ts

@@ -0,0 +1,47 @@
+type GroupedItem<T>
+	= | { item: T; type: "single" }
+		| { items: [T, T, ...T[]]; key: string; type: "group" };
+
+function groupItems<T>(
+	items: readonly T[],
+	keyOf: (item: T) => null | string,
+): GroupedItem<T>[] {
+	const result: GroupedItem<T>[] = [];
+	const indices = new Map<string, number>();
+
+	for (const item of items) {
+		const key = keyOf(item);
+
+		if (key === null) {
+			result.push({ item, type: "single" });
+			continue;
+		}
+
+		const index = indices.get(key);
+
+		if (index === undefined) {
+			indices.set(key, result.length);
+			result.push({ item, type: "single" });
+			continue;
+		}
+
+		// eslint-disable-next-line security/detect-object-injection -- Map-owned index.
+		const existing = result[index];
+
+		if (existing?.type === "single") {
+			// eslint-disable-next-line security/detect-object-injection -- Map-owned index.
+			result[index] = {
+				items: [existing.item, item],
+				key,
+				type: "group",
+			};
+		}
+		else if (existing) {
+			existing.items.push(item);
+		}
+	}
+
+	return result;
+}
+
+export { groupItems };

src/shared/lib/index.ts

@@ -1,13 +1,23 @@
 export { compareDateDesc, defaultPeriod, isValidPeriod, moscowDate } from "./calendar";
 export { calendarDate } from "./calendar.schema";
+export {
+	type Decimal,
+	decimalFromString,
+	decimalToString,
+	sumDecimals,
+	sumMoney,
+} from "./decimal";
 export {
 	formatChartValue,
 	formatDate,
 	formatDecimal,
 	formatMoney,
+	formatSnapshotDay,
 	formatSnapshotTime,
 	instrumentLogoUrl,
 	portfolioCategoryPresentation,
 } from "./display";
+export { groupItems } from "./group-items";
 export { useInitialAvailability } from "./initial-availability";
+export { totalText } from "./total-text";
 export { useUrlPeriod } from "./useUrlPeriod";

src/shared/lib/total-text.ts

@@ -0,0 +1,13 @@
+import { formatMoney } from "./display";
+
+type Money = { currency: string; value: string };
+
+function totalText(totals: Money[] | null, isSigned: boolean): string {
+	return totals
+		? totals.map(total =>
+				formatMoney(total, { withSign: isSigned || undefined }),
+			).join(", ")
+		: "";
+}
+
+export { totalText };