Files
feuerwerk/tests/ui/scroll-container.test.ts
T
adminandClaude Opus 5 a65132bb5a
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Scrolling content is narrowed by the scrollbar width while the scrollbar is shown, so it no longer sits under the bar
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-18 07:29:58 +02:00

64 lines
2.2 KiB
TypeScript

import { describe, expect, it } from 'vitest';
import { ScrollContainer, Spacer, Theme, VStack } from '../../src/ui';
/** Row tops after a layout; an unlaid-out stack leaves every child at 0. */
const tops = (stack: VStack) => stack.children.map((c) => c.y);
describe('a scroll container told its content changed', () => {
it('lays out rows that leave the height pinned to the viewport', () => {
const scroll = new ScrollContainer();
scroll.resize(200, 300);
const rows = new VStack();
// The list tab hands over the stack before filling it, so the empty content is measured first
// and pinned to the viewport height.
scroll.setContent(rows);
rows.add(new Spacer(20));
rows.add(new Spacer(20));
rows.add(new Spacer(20));
// 60 < 300, so the content keeps the height it already had: `resize` alone would see no
// change and skip the layout, leaving all three rows stacked at the top.
scroll.relayoutContent();
expect(tops(rows)).toEqual([0, 20, 40]);
});
it('still lays out rows that make the content taller than the viewport', () => {
const scroll = new ScrollContainer();
scroll.resize(200, 50);
const rows = new VStack();
scroll.setContent(rows);
rows.add(new Spacer(20));
rows.add(new Spacer(20));
rows.add(new Spacer(20));
scroll.relayoutContent();
expect(tops(rows)).toEqual([0, 20, 40]);
expect(scroll.maxScroll).toBe(10);
});
});
describe('a scroll container and its scrollbar', () => {
const filled = (viewportH: number, rowCount: number) => {
const scroll = new ScrollContainer();
scroll.resize(200, viewportH);
const rows = new VStack();
for (let i = 0; i < rowCount; i++) rows.add(new Spacer(20));
scroll.setContent(rows);
return { scroll, rows };
};
it('gives content that fits the full width', () => {
expect(filled(300, 3).rows.w).toBe(200);
});
it('keeps the gutter free for the bar while the content scrolls', () => {
expect(filled(50, 3).rows.w).toBe(200 - Theme.scrollbarWidth);
});
it('hands the gutter back once the content fits again', () => {
const { scroll, rows } = filled(50, 3);
scroll.resize(200, 300);
expect(rows.w).toBe(200);
});
});