fix: ensure directory exists when writing an Asset

It's possible that assets get written before the actual markdown files.
In that case, the target directory may not exist yet and has to be
created first.

Author: JohannesRudolph

src/AssetWriter.ts

@@ -13,10 +13,15 @@ export class AssetWriter {
   constructor(readonly dir: string) {}
 
   async store(name: string, buffer: Buffer) {
+    await fs.mkdir(this.dir, { recursive: true });
     await fs.writeFile(`${this.dir}/${name}`, buffer);
   }
 
-  async download(url: string, fileName: string, context: RenderingLoggingContext) {
+  async download(
+    url: string,
+    fileName: string,
+    context: RenderingLoggingContext
+  ) {
     // the got http lib promises to do proper user-agent compliant http caching
     // see https://github.com/sindresorhus/got/blob/main/documentation/cache.md
 
@@ -29,9 +34,8 @@ export class AssetWriter {
     );
     const imageFile = fileName + "." + ext;
 
-    context.info(
-      `downloading (cached: ${response.isFromCache}): ${imageFile}`
-    );
+    const cacheInfo = response.isFromCache ? " (from cache)" : "";
+    context.info(`downloading ${imageFile}` + cacheInfo);
     await this.store(imageFile, response.rawBody);
 
     return imageFile;