Compatibility with vim-markdownfmt

lib/cli.coffee

@@ -1,5 +1,6 @@
 {ArgumentParser} = require 'argparse'
 
+fs = require 'fs'
 packageInfo = require '../package'
 tidyMarkdown = require './'
 
@@ -10,6 +11,16 @@ argparser = new ArgumentParser(
   version: packageInfo.version
 )
 
+argparser.addArgument(
+  ['path'],
+  action: 'store',
+  type: 'string',
+  help: 'Filename to read (default: STDIN)'
+  defaultValue: null,
+  nargs: '?',
+  required: false
+)
+
 argparser.addArgument(
   ['--no-ensure-first-header-is-h1']
   action: 'storeFalse'
@@ -20,13 +31,33 @@ argparser.addArgument(
   dest: 'ensureFirstHeaderIsH1'
 )
 
+argparser.addArgument(
+  ['-w', '--write']
+  action: 'storeTrue',
+  help: 'Write result to (source) file instead of stdout',
+  dest: 'write'
+)
+
 argv = argparser.parseArgs()
 
-process.stdin.setEncoding 'utf8'
-process.stdin.on 'readable', ->
+
+if argv.path is null
+  input = process.stdin
+  input.setEncoding 'utf8'
+else
+  input = fs.createReadStream(argv.path, {encoding: 'utf8'})
+
+input.on 'readable', ->
   buffer = ''
-  while (chunk = process.stdin.read()) isnt null
+  while (chunk = input.read()) isnt null
     buffer += chunk
+  input.close()
+
+  if argv.write
+    output = fs.createWriteStream(argv.path, {encoding: 'utf8'})
+  else
+    output = process.stdout
+
   if buffer isnt ''
-    process.stdout.write tidyMarkdown(buffer, argv)
+    output.write tidyMarkdown(buffer, argv)
   return