Add a bit of laziness

middleman-core/lib/middleman-core/sources.rb

@@ -1,4 +1,5 @@
 require 'middleman-core/contracts'
+require 'backports/2.0.0/enumerable/lazy'
 
 module Middleman
   # The standard "record" that contains information about a file on disk.
@@ -168,6 +169,7 @@ module Middleman
     Contract Symbol, String, Maybe[Bool] => Maybe[SourceFile]
     def find(type, path, glob=false)
       watchers
+          .lazy
           .select { |d| d.type == type }
           .map { |d| d.find(path, glob) }
           .reject { |d| d.nil? }
@@ -182,6 +184,7 @@ module Middleman
     Contract Symbol, String => Bool
     def exists?(type, path)
       watchers
+          .lazy
           .select { |d| d.type == type }
           .any? { |d| d.exists?(path) }
     end