Warn about incompatible renderings on first PDF conversion with Firefox

src/converter.ts

@@ -124,6 +124,8 @@ const stripBOM = (s: string) => (s.charCodeAt(0) === 0xfeff ? s.slice(1) : s)
 export class Converter {
   readonly options: ConverterOption
 
+  private _firefoxPDFConversionWarning = false
+
   constructor(opts: ConverterOption) {
     this.options = opts
   }
@@ -252,7 +254,7 @@ export class Converter {
         if (opts.onConverted) opts.onConverted({ file, newFile, template })
       }
 
-      // #convertFile must return a single file to serve in server
+      // convertFile must return a single file to serve in server
       return { file, template, newFile: files[0] }
     } else {
       // Try conversion with specific template to scan using resources
@@ -301,6 +303,17 @@ export class Converter {
 
     const ret = file.convert(this.options.output, { extension: 'pdf' })
 
+    // Generate PDF
+    const browser = await browserManager.browserForConversion()
+
+    if (browser.kind === 'firefox' && !this._firefoxPDFConversionWarning) {
+      this._firefoxPDFConversionWarning = true
+
+      warn(
+        'Using Firefox to convert Markdown to PDF: The output may include some incompatible renderings compared to the PDF generated by Chrome.'
+      )
+    }
+
     let outlineData: OutlineData | undefined
 
     ret.buffer = Buffer.from(