Reducing browser spinner time (#1157)

lib/data-url-plugin.js

@@ -14,28 +14,40 @@ import { promises as fs } from 'fs';
 
 import { lookup as lookupMime } from 'mime-types';
 
-const prefix = 'data-url:';
+const prefix = /^data-url(-text)?:/;
 
 export default function dataURLPlugin() {
   return {
     name: 'data-url-plugin',
     async resolveId(id, importer) {
-      if (!id.startsWith(prefix)) return;
+      const match = prefix.exec(id);
+      if (!match) return;
       return (
-        prefix + (await this.resolve(id.slice(prefix.length), importer)).id
+        match[0] + (await this.resolve(id.slice(match[0].length), importer)).id
       );
     },
     async load(id) {
-      if (!id.startsWith(prefix)) return;
-      const realId = id.slice(prefix.length);
+      const match = prefix.exec(id);
+      if (!match) return;
+
+      const isText = !!match[1];
+      const realId = id.slice(match[0].length);
       this.addWatchFile(realId);
 
       const source = await fs.readFile(realId);
       const type = lookupMime(realId) || 'text/plain';
 
-      return `export default 'data:${type};base64,${source.toString(
-        'base64',
-      )}';`;
+      if (isText) {
+        const encodedBody = encodeURIComponent(source.toString('utf8'));
+
+        return `export default ${JSON.stringify(
+          `data:${type};charset=utf-8,${encodedBody}`,
+        )};`;
+      }
+
+      return `export default ${JSON.stringify(
+        `data:${type};base64,${source.toString('base64')}`,
+      )};`;
     },
   };
 }