--- a/.eslintignore
+++ b/.eslintignore
@@ -1,11 +1,15 @@
 # Always ignore node_modules.
 **/node_modules/**/*.*
 
+# Include these to speed up ESLint, see bug 1347906.
+.hg
+.git
+
 # Exclude expected objdirs.
 obj*/**
 
 # We ignore all these directories by default, until we get them enabled.
 # If you are enabling a directory, please add directory specific exclusions
 # below.
 addon-sdk/**
 build/**