36 lines
1.2 KiB
TypeScript
36 lines
1.2 KiB
TypeScript
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import { describe, expect, it } from "vitest";
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import { formatCompact } from "./formatNumber";
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describe("formatCompact", () => {
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it("formats values below 1000 with locale grouping and no suffix", () => {
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expect(formatCompact(0)).toBe("0");
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expect(formatCompact(999)).toBe("999");
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});
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it("formats K/M/B bands", () => {
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expect(formatCompact(1000)).toBe("1K");
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expect(formatCompact(1500)).toBe("1.5K");
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expect(formatCompact(1_200_000)).toBe("1.2M");
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expect(formatCompact(1_000_000_000)).toBe("1B");
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});
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it("promotes to the next unit when rounding carries to 1000", () => {
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// 999_999 / 1e3 = 999.999 -> toFixed(1) rounds to "1000.0"; must render "1M".
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expect(formatCompact(999_999)).toBe("1M");
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expect(formatCompact(999_950)).toBe("1M");
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expect(formatCompact(999_999_999)).toBe("1B");
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expect(formatCompact(999_950_000)).toBe("1B");
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});
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it("does not promote just below the rounding boundary", () => {
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expect(formatCompact(999_499)).toBe("999.5K");
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expect(formatCompact(999_499_999)).toBe("999.5M");
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});
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it("returns 0 for non-finite or negative input", () => {
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expect(formatCompact(Number.NaN)).toBe("0");
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expect(formatCompact(-5)).toBe("0");
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});
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});
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