refactor(timeline): move pure month-bucket math to $lib/shared/utils/monthBuckets

Relocate the 10 pure helpers (monthBoundaryFrom/To, buildMonthSequence,
fillDensityGaps, clipBucketsToRange, aggregateToYears, selectionBoundaryFrom/To,
tickIndicesFor, formatTickLabel) and their unit tests out of document/timeline.ts
into a shared module so lib/timeline/ can consume them without importing
lib/document/. The /api/documents/density glue (buildDensityUrl, fetchDensity,
DensityState, DensityFilters) stays in document/timeline.ts. Re-point the three
density components and the density-filter spec at the shared module.

Refs #779
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
Marcel
2026-06-13 19:18:50 +02:00
parent 1348255ae3
commit 1dc3b91458
8 changed files with 435 additions and 426 deletions

View File

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import { describe, it, expect } from 'vitest';
import {
monthBoundaryFrom,
monthBoundaryTo,
buildMonthSequence,
fillDensityGaps,
aggregateToYears,
selectionBoundaryFrom,
selectionBoundaryTo,
clipBucketsToRange,
tickIndicesFor,
formatTickLabel
} from './monthBuckets';
describe('monthBoundaryFrom', () => {
it('returns the first day of the given month', () => {
expect(monthBoundaryFrom('1915-08')).toBe('1915-08-01');
});
it('handles January', () => {
expect(monthBoundaryFrom('1920-01')).toBe('1920-01-01');
});
});
describe('monthBoundaryTo', () => {
it('returns the last day of a 31-day month', () => {
expect(monthBoundaryTo('1915-08')).toBe('1915-08-31');
});
it('returns the last day of a 30-day month', () => {
expect(monthBoundaryTo('1915-04')).toBe('1915-04-30');
});
it('returns 28 for February in a non-leap year', () => {
expect(monthBoundaryTo('1915-02')).toBe('1915-02-28');
});
it('returns 29 for February in a leap year', () => {
expect(monthBoundaryTo('1916-02')).toBe('1916-02-29');
});
});
describe('buildMonthSequence', () => {
it('returns a single month when min and max are in the same month', () => {
expect(buildMonthSequence('1915-08-03', '1915-08-22')).toEqual(['1915-08']);
});
it('returns months from minDate through maxDate inclusive', () => {
expect(buildMonthSequence('1915-08-03', '1915-11-15')).toEqual([
'1915-08',
'1915-09',
'1915-10',
'1915-11'
]);
});
it('crosses year boundaries correctly', () => {
expect(buildMonthSequence('1915-11-30', '1916-02-01')).toEqual([
'1915-11',
'1915-12',
'1916-01',
'1916-02'
]);
});
it('returns empty array when minDate or maxDate is null', () => {
expect(buildMonthSequence(null, '1915-08-01')).toEqual([]);
expect(buildMonthSequence('1915-08-01', null)).toEqual([]);
expect(buildMonthSequence(null, null)).toEqual([]);
});
});
describe('fillDensityGaps', () => {
it('returns empty array when minDate or maxDate is null', () => {
expect(fillDensityGaps([], null, null)).toEqual([]);
});
it('preserves existing buckets and adds zero-count buckets for missing months', () => {
const buckets = [
{ month: '1915-08', count: 5 },
{ month: '1915-11', count: 2 }
];
const result = fillDensityGaps(buckets, '1915-08-03', '1915-11-30');
expect(result).toEqual([
{ month: '1915-08', count: 5 },
{ month: '1915-09', count: 0 },
{ month: '1915-10', count: 0 },
{ month: '1915-11', count: 2 }
]);
});
it('returns all-zero sequence when buckets array is empty', () => {
const result = fillDensityGaps([], '1915-08-03', '1915-10-15');
expect(result).toEqual([
{ month: '1915-08', count: 0 },
{ month: '1915-09', count: 0 },
{ month: '1915-10', count: 0 }
]);
});
it('keeps results sorted chronologically even when buckets arrive out of order', () => {
const buckets = [
{ month: '1915-10', count: 3 },
{ month: '1915-08', count: 1 }
];
const result = fillDensityGaps(buckets, '1915-08-01', '1915-10-31');
expect(result.map((b) => b.month)).toEqual(['1915-08', '1915-09', '1915-10']);
});
});
describe('aggregateToYears', () => {
it('returns empty array for empty input', () => {
expect(aggregateToYears([])).toEqual([]);
});
it('sums counts within the same year', () => {
const result = aggregateToYears([
{ month: '1915-08', count: 5 },
{ month: '1915-09', count: 2 },
{ month: '1915-10', count: 8 }
]);
expect(result).toEqual([{ month: '1915', count: 15 }]);
});
it('produces one bucket per distinct year, sorted chronologically', () => {
const result = aggregateToYears([
{ month: '1916-01', count: 3 },
{ month: '1915-08', count: 5 },
{ month: '1916-04', count: 7 },
{ month: '1914-12', count: 1 }
]);
expect(result).toEqual([
{ month: '1914', count: 1 },
{ month: '1915', count: 5 },
{ month: '1916', count: 10 }
]);
});
});
describe('clipBucketsToRange', () => {
const buckets = [
{ month: '1915-08', count: 5 },
{ month: '1915-09', count: 2 },
{ month: '1915-10', count: 8 },
{ month: '1915-11', count: 3 }
];
it('returns the original buckets when range bounds are null', () => {
expect(clipBucketsToRange(buckets, null, null)).toBe(buckets);
});
it('keeps only buckets whose month falls within the range', () => {
expect(clipBucketsToRange(buckets, '1915-09-01', '1915-10-31')).toEqual([
{ month: '1915-09', count: 2 },
{ month: '1915-10', count: 8 }
]);
});
it('returns an empty array when the range excludes everything', () => {
expect(clipBucketsToRange(buckets, '1916-01-01', '1916-12-31')).toEqual([]);
});
it('treats partial dates correctly when bounds cross month boundaries', () => {
expect(clipBucketsToRange(buckets, '1915-09-15', '1915-10-15')).toEqual([
{ month: '1915-09', count: 2 },
{ month: '1915-10', count: 8 }
]);
});
});
describe('selectionBoundaryFrom / To', () => {
it('handles month labels (YYYY-MM)', () => {
expect(selectionBoundaryFrom('1915-08')).toBe('1915-08-01');
expect(selectionBoundaryTo('1915-08')).toBe('1915-08-31');
});
it('handles year labels (YYYY)', () => {
expect(selectionBoundaryFrom('1915')).toBe('1915-01-01');
expect(selectionBoundaryTo('1915')).toBe('1915-12-31');
});
});
describe('tickIndicesFor', () => {
it('returns no indices for an empty bucket list', () => {
expect(tickIndicesFor([])).toEqual([]);
});
it('picks years divisible by 25 when the year span exceeds 120', () => {
const buckets = Array.from({ length: 150 }, (_, i) => ({
month: String(1875 + i),
count: 1
}));
const ticks = tickIndicesFor(buckets);
const labels = ticks.map((i) => buckets[i].month);
expect(labels).toEqual(['1875', '1900', '1925', '1950', '1975', '2000']);
});
it('picks years divisible by 10 for medium ranges (~50 years)', () => {
const buckets = Array.from({ length: 50 }, (_, i) => ({
month: String(1900 + i),
count: 1
}));
const ticks = tickIndicesFor(buckets);
const labels = ticks.map((i) => buckets[i].month);
expect(labels).toEqual(['1900', '1910', '1920', '1930', '1940']);
});
it('picks January boundaries for long month ranges', () => {
const buckets = [
{ month: '1914-08', count: 1 },
{ month: '1914-09', count: 1 },
{ month: '1914-10', count: 1 },
{ month: '1914-11', count: 1 },
{ month: '1914-12', count: 1 },
{ month: '1915-01', count: 1 },
{ month: '1915-02', count: 1 },
{ month: '1915-03', count: 1 },
{ month: '1915-04', count: 1 },
{ month: '1915-05', count: 1 },
{ month: '1915-06', count: 1 },
{ month: '1915-07', count: 1 },
{ month: '1915-08', count: 1 },
{ month: '1915-09', count: 1 },
{ month: '1915-10', count: 1 },
{ month: '1915-11', count: 1 },
{ month: '1915-12', count: 1 },
{ month: '1916-01', count: 1 },
{ month: '1916-02', count: 1 }
];
const ticks = tickIndicesFor(buckets);
expect(ticks.map((i) => buckets[i].month)).toEqual(['1915-01', '1916-01']);
});
it('falls back to evenly spaced ticks for short month ranges (12 months)', () => {
const buckets = Array.from({ length: 12 }, (_, i) => ({
month: `1905-${String(i + 1).padStart(2, '0')}`,
count: 1
}));
const ticks = tickIndicesFor(buckets);
expect(ticks.length).toBeGreaterThanOrEqual(5);
expect(ticks.length).toBeLessThanOrEqual(7);
expect(ticks[0]).toBe(0);
});
});
describe('formatTickLabel', () => {
it('returns the year string unchanged for year labels', () => {
expect(formatTickLabel('1905', 'en-US')).toBe('1905');
});
it('formats month labels with the year by default', () => {
const result = formatTickLabel('1905-06', 'en-US');
expect(result).toMatch(/Jun/);
expect(result).toMatch(/1905/);
});
it('omits the year when omitYear is true', () => {
const result = formatTickLabel('1905-06', 'en-US', true);
expect(result).toMatch(/Jun/);
expect(result).not.toMatch(/1905/);
});
});