Add file-level bundle size diffs to CI

GitOrigin-RevId: b41274fd1a2e33834357fa13a8a3df534654d845

Author: aleksigron

rollup.config.esm.ts

@@ -68,6 +68,14 @@ function esmConfig(dir: string, workerSuffix: string, emitVisualizer = false): R
                 sourcemap: false,
                 title: 'GL JS ESM bundle',
             }),
+            emitVisualizer && visualizer({
+                filename: `${dir}bundle-stats.json`,
+                template: 'raw-data',
+                gzipSize: true,
+                brotliSize: false,
+                sourcemap: false,
+                projectRoot: process.cwd(),
+            }),
         ],
     };
 }

test/unit/internal/compare-bundle-stats.test.ts

@@ -0,0 +1,140 @@
+import {describe, expect, test} from 'vitest';
+import {
+    diffBundleStats,
+    diffBundleStatsData,
+    formatBundleDiffMarkdown,
+    parseBundleStats,
+    type VisualizerData,
+} from '../../../internal/scripts/compare-bundle-stats.js';
+
+const baseStats: VisualizerData = {
+    version: 2,
+    options: {gzip: true, brotli: false},
+    nodeMetas: {
+        'meta-a': {
+            id: 'src/foo.ts',
+            moduleParts: {'mapbox-gl': 'part-a1', core: 'part-a2'},
+        },
+        'meta-b': {
+            id: 'src/bar.ts',
+            moduleParts: {'mapbox-gl': 'part-b1'},
+        },
+        'meta-c': {
+            id: 'src/removed.ts',
+            moduleParts: {shared: 'part-c1'},
+        },
+    },
+    nodeParts: {
+        'part-a1': {renderedLength: 500, gzipLength: 200, metaUid: 'meta-a'},
+        'part-a2': {renderedLength: 300, gzipLength: 150, metaUid: 'meta-a'},
+        'part-b1': {renderedLength: 1000, gzipLength: 400, metaUid: 'meta-b'},
+        'part-c1': {renderedLength: 800, gzipLength: 300, metaUid: 'meta-c'},
+    },
+};
+
+const headStats: VisualizerData = {
+    version: 2,
+    options: {gzip: true, brotli: false},
+    nodeMetas: {
+        'meta-a': {
+            id: 'src/foo.ts',
+            moduleParts: {'mapbox-gl': 'part-a1', core: 'part-a2'},
+        },
+        'meta-b': {
+            id: 'src/bar.ts',
+            moduleParts: {'mapbox-gl': 'part-b1'},
+        },
+        'meta-d': {
+            id: 'src/new.ts',
+            moduleParts: {shared: 'part-d1'},
+        },
+    },
+    nodeParts: {
+        'part-a1': {renderedLength: 500, gzipLength: 310, metaUid: 'meta-a'},
+        'part-a2': {renderedLength: 300, gzipLength: 150, metaUid: 'meta-a'},
+        'part-b1': {renderedLength: 1000, gzipLength: 300, metaUid: 'meta-b'},
+        'part-d1': {renderedLength: 600, gzipLength: 250, metaUid: 'meta-d'},
+    },
+};
+
+describe('compare-bundle-stats', () => {
+    test('parseBundleStats aggregates gzip per file across bundles', () => {
+        const files = parseBundleStats(baseStats);
+        expect(files.get('src/foo.ts')).toEqual({file: 'src/foo.ts', gzip: 350, rendered: 800});
+        expect(files.get('src/bar.ts')).toEqual({file: 'src/bar.ts', gzip: 400, rendered: 1000});
+    });
+
+    test('diffBundleStats reports added, removed, and changed files', () => {
+        const head = parseBundleStats(headStats);
+        const base = parseBundleStats(baseStats);
+        const result = diffBundleStats(head, base);
+
+        const byFile = new Map(result.entries.map((entry) => [entry.file, entry]));
+
+        expect(byFile.get('src/foo.ts')).toMatchObject({
+            baseGzip: 350,
+            headGzip: 460,
+            delta: 110,
+            status: 'changed',
+        });
+        expect(byFile.get('src/bar.ts')).toMatchObject({
+            baseGzip: 400,
+            headGzip: 300,
+            delta: -100,
+            status: 'changed',
+        });
+        expect(byFile.get('src/new.ts')).toMatchObject({
+            baseGzip: 0,
+            headGzip: 250,
+            delta: 250,
+            status: 'added',
+        });
+        expect(byFile.get('src/removed.ts')).toMatchObject({
+            baseGzip: 300,
+            headGzip: 0,
+            delta: -300,
+            status: 'removed',
+        });
+    });
+
+    test('diffBundleStats filters changes below 20 bytes', () => {
+        const head = parseBundleStats(headStats);
+        const base = parseBundleStats(baseStats);
+        head.set('src/tiny.ts', {file: 'src/tiny.ts', gzip: 115, rendered: 115});
+        base.set('src/tiny.ts', {file: 'src/tiny.ts', gzip: 100, rendered: 100});
+        const result = diffBundleStats(head, base);
+
+        expect(result.entries.find((entry) => entry.file === 'src/tiny.ts')).toBeUndefined();
+    });
+
+    test('diffBundleStats sorts by absolute delta', () => {
+        const result = diffBundleStatsData(headStats, baseStats);
+
+        expect(result.entries[0].file).toBe('src/removed.ts');
+        expect(result.entries[1].file).toBe('src/new.ts');
+        expect(result.entries[2].file).toBe('src/foo.ts');
+        expect(result.entries[3].file).toBe('src/bar.ts');
+    });
+
+    test('formatBundleDiffMarkdown includes table headers and status labels', () => {
+        const result = diffBundleStatsData(headStats, baseStats);
+        const markdown = formatBundleDiffMarkdown(result);
+
+        expect(markdown).toContain('### File-level changes (gzip, top 20)');
+        expect(markdown).toContain('| File | Base | Head | Δ | Δ% |');
+        expect(markdown).toContain('`src/new.ts` (new)');
+        expect(markdown).toContain('`src/removed.ts` (removed)');
+        expect(markdown).toContain('-0.30 kB');
+        expect(markdown).toContain('+0.25 kB');
+    });
+
+    test('rejects unsupported visualizer data versions', () => {
+        const invalid: VisualizerData = {
+            version: 99,
+            options: baseStats.options,
+            nodeMetas: baseStats.nodeMetas,
+            nodeParts: baseStats.nodeParts,
+        };
+        expect(() => parseBundleStats(invalid)).toThrow(/Unsupported bundle-stats version/);
+    });
+});