changing file permisisons

bin/sketch

@@ -0,0 +1,57 @@
+#!/usr/bin/env ruby
+require 'fileutils'
+
+PROGNAME = 'pre-commit (auto-generate sketch previews)'
+
+def main
+  progress "Installing sketchtool"
+  system!(%W[/Applications/Sketch.app/Contents/Resources/sketchtool/install.sh])
+
+  progress "Looking for changed or added .sketch files"
+  diff_output = capture!(%W[git diff --name-only --cached --pretty=format:])
+  sketch_files = diff_output.split("\n").grep(/\.sketch\z/)
+  if sketch_files.empty?
+    progress "No sketch files to create preview images for in this commit!"
+  end
+  puts sketch_files
+
+  sketch_files.each do |f|
+    unless File.exist?(f)
+      progress "#{f} does not exist (anymore?)"
+      next
+    end
+
+    png_output_dir = f.sub(/\.sketch\z/, '') + '-sketch-previews'
+    progress "deleting old previews"
+    FileUtils.rm_rf(png_output_dir)
+
+    progress "exporting pages"
+    cmd = %W[sketchtool --overwriting=YES --output=#{png_output_dir} export pages #{f}]
+    system!(cmd)
+
+    progress "adding to git"
+    system!(%W[git add #{png_output_dir}])
+  end
+end
+
+def system!(cmd)
+  puts "running: #{cmd.join(' ')}"
+  abort failure_message(cmd) unless system(*cmd)
+end
+
+def capture!(cmd)
+  puts "capturing: #{cmd.join(' ')}"
+  result = IO.popen(cmd) { |io| io.read }
+  abort failure_message(cmd) unless $?.success?
+  result
+end
+
+def failure_message(cmd)
+  "#{PROGNAME}: command failed: #{cmd.join(' ')}"
+end
+
+def progress(msg)
+  puts "#{PROGNAME}: #{msg}"
+end
+
+main

package.json

@@ -14,7 +14,7 @@
   },
   "scripts": {
     "test": "make test",
-    "precommit": "make -j4 lint",
+    "precommit": "make -j4 lint && ./bin/sketch",
     "prepush": "make test"
   },
   "dependencies": {