feat: run script before the page is fully loaded

src/main.ts

@@ -1,7 +1,7 @@
 import './meta'
 
 import FileSaver from 'file-saver'
-import { waitForDocumentLoaded, console } from './utils'
+import { waitForSheetLoaded, console } from './utils'
 import { downloadPDF } from './pdf'
 import { downloadMscz } from './mscz'
 import { getFileUrl } from './file'
@@ -143,4 +143,4 @@ const main = (): void => {
 }
 
 // eslint-disable-next-line @typescript-eslint/no-floating-promises
-waitForDocumentLoaded().then(main)
+waitForSheetLoaded().then(main)

src/utils.ts

@@ -136,3 +136,23 @@ export const waitForDocumentLoaded = (): Promise<void> => {
     return Promise.resolve()
   }
 }
+
+/**
+ * Run script before the page is fully loaded
+ */
+export const waitForSheetLoaded = (): Promise<void> => {
+  if (document.readyState !== 'complete') {
+    return new Promise(resolve => {
+      const observer = new MutationObserver(() => {
+        const img = document.querySelector('img')
+        if (img) {
+          resolve()
+          observer.disconnect()
+        }
+      })
+      observer.observe(document.body, { childList: true, subtree: true })
+    })
+  } else {
+    return Promise.resolve()
+  }
+}