decaffeinate: Rename CommandRunner.coffee and 25 other files from .coffee to .js

app/coffee/ContentTypeMapper.js

@@ -0,0 +1,24 @@
+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'