Wait for next HTML animation frame when rendering

CHANGELOG.md

@@ -4,7 +4,7 @@
 
 ### Added
 
-- Introduce parallelism for batch conversion: `--parallel` / `-P` ([#509](https://github.com/marp-team/marp-cli/issues/509), [#628](https://github.com/marp-team/marp-cli/pull/628))
+- Introduce parallelism for batch conversion: `--parallel` / `-P` ([#509](https://github.com/marp-team/marp-cli/issues/509), [#628](https://github.com/marp-team/marp-cli/pull/628), [#629](https://github.com/marp-team/marp-cli/pull/629))
 
 ### Fixed
 

src/converter.ts

@@ -668,6 +668,15 @@ export class Converter {
           await page.goto('data:text/html,', waitForOptions)
           await page.setContent(baseFile.buffer!.toString(), waitForOptions)
         }
+
+        // Wait for next frame (In parallel rendering, it may be needed to wait for the first rendering)
+        await page.evaluate(async () => {
+          /* c8 ignore start */
+          await new Promise<void>((resolve) =>
+            window.requestAnimationFrame(() => resolve())
+          )
+          /* c8 ignore end */
+        })
       }
 
       try {

test/converter.ts

@@ -1271,7 +1271,7 @@ describe('Converter', () => {
             expect(secondCall[1]).toBeInstanceOf(Buffer)
             expect((secondCall[1] as Buffer).length).toBeLessThan(jpeg.length)
           },
-          timeout
+          timeoutLarge
         )
       })
 
@@ -1315,7 +1315,7 @@ describe('Converter', () => {
             expect(secondCall[1]).toBeInstanceOf(Buffer)
             expect((secondCall[1] as Buffer).length).toBeLessThan(jpeg.length)
           },
-          timeout
+          timeoutLarge
         )
       })
     })