diff --git a/build/lib/optimize.ts b/build/lib/optimize.ts
index 2822803f9f7..86400889de8 100644
--- a/build/lib/optimize.ts
+++ b/build/lib/optimize.ts
@@ -67,7 +67,7 @@ function loader(src: string, bundledFileHeader: string, bundleLoader: boolean):
 					isFirst = false;
 					this.emit('data', new VinylFile({
 						path: 'fake',
-						base: '',
+						base: '.',
 						contents: Buffer.from(bundledFileHeader)
 					}));
 					this.emit('data', data);
@@ -102,7 +102,7 @@ function toConcatStream(src: string, bundledFileHeader: string, sources: bundle.
 
 	const treatedSources = sources.map(function (source) {
 		const root = source.path ? REPO_ROOT_PATH.replace(/\\/g, '/') : '';
-		const base = source.path ? root + `/${src}` : '';
+		const base = source.path ? root + `/${src}` : '.';
 		const path = source.path ? root + '/' + source.path.replace(/\\/g, '/') : 'fake';
 		const contents = source.path ? fileContentMapper(source.contents, path) : source.contents;