fix: forward type and quality options from toBlob to canvasToBlob

[Kebechet]

Problem

toBlob forwards its options to toCanvas, but then calls canvasToBlob without them:

const canvas = await toCanvas(node, options)
const blob = await canvasToBlob(canvas)

canvasToBlob accepts type and quality and defaults them to image/png / 1, so toBlob(node, { type: 'image/jpeg', quality: 0.5 }) silently returns a PNG at quality 1 — the requested type and quality are dropped on the floor.

Fix

Pass options through to canvasToBlob. One line; canvasToBlob already implements the handling.

Tests

test/spec/to-blob.spec.ts:

• default capture still produces image/png;
• type: 'image/jpeg' produces a blob with type === 'image/jpeg' — on current master this fails with image/png;
• a JPEG at quality: 0.01 is smaller than the same capture at quality: 1 — on current master both blobs are byte-identical PNGs.

[Copilot]

🟡 Changes recommended

The new tests likely violate existing spec-file lint conventions and include a null-dereference hazard, and the change exposes an existing quality: 0 handling bug that should be addressed for correctness.

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Pull request overview

This PR fixes toBlob so it correctly forwards type/quality export options through to canvasToBlob, aligning blob output with the options already respected by toCanvas and canvasToBlob.

Changes:

• Pass options from toBlob into canvasToBlob so requested type/quality are honored.
• Add new toBlob specs verifying default image/png, honoring type, and honoring quality (via size comparison).

File summaries

File	Description
src/index.ts	Forwards options into canvasToBlob so blob encoding honors type/quality.
test/spec/to-blob.spec.ts	Adds regression coverage for toBlob defaults and option forwarding.

Review details

Suppressed comments (1)

test/spec/to-blob.spec.ts:40

• This test dereferences lowQualityBlob/highQualityBlob with ! without asserting they are non-null first; if toBlob returns null (e.g., unsupported type), the test will throw a TypeError instead of failing with a clear expectation message.

      .then(([lowQualityBlob, highQualityBlob]) => {
        expect(lowQualityBlob!.size).toBeLessThan(highQualityBlob!.size)
        done()

• Files reviewed: 2/2 changed files
• Comments generated: 2
• Review effort level: Lite

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