decaffeinate: Convert CommandRunner.coffee and 25 other files to JS

app/coffee/ContentTypeMapper.js

@@ -1,24 +1,28 @@
-Path = require 'path'
+let ContentTypeMapper;
+const Path = require('path');
 
-# here we coerce html, css and js to text/plain,
-# otherwise choose correct mime type based on file extension,
-# falling back to octet-stream
-module.exports = ContentTypeMapper =
-	map: (path) ->
-		switch Path.extname(path)
-			when '.txt', '.html', '.js', '.css', '.svg'
-				return 'text/plain'
-			when '.csv'
-				return 'text/csv'
-			when '.pdf'
-				return 'application/pdf'
-			when '.png'
-				return 'image/png'
-			when '.jpg', '.jpeg'
-				return 'image/jpeg'
-			when '.tiff'
-				return 'image/tiff'
-			when '.gif'
-				return 'image/gif'
-			else
-				return 'application/octet-stream'
+// here we coerce html, css and js to text/plain,
+// otherwise choose correct mime type based on file extension,
+// falling back to octet-stream
+module.exports = (ContentTypeMapper = {
+	map(path) {
+		switch (Path.extname(path)) {
+			case '.txt': case '.html': case '.js': case '.css': case '.svg':
+				return 'text/plain';
+			case '.csv':
+				return 'text/csv';
+			case '.pdf':
+				return 'application/pdf';
+			case '.png':
+				return 'image/png';
+			case '.jpg': case '.jpeg':
+				return 'image/jpeg';
+			case '.tiff':
+				return 'image/tiff';
+			case '.gif':
+				return 'image/gif';
+			default:
+				return 'application/octet-stream';
+		}
+	}
+});