A complete list of file types, extensions and mime types in JavaScript.
Stretchr.Filetypes.descriptionFor("txt");
//= "Text file"
Stretchr.Filetypes.descriptionFor("text/plain");
//= "Text file"
Stretchr.Filetypes.mimeFor("txt");
//= "text/plain"
Stretchr.Filetypes.extensionFor("text/plain")
//= "txt"