chore: support powershell file(*.ps1)

PR-URL: #6
Credit: @NoDocCat
Close: #6
Reviewed-by: @isaacs

index.js

@@ -4,11 +4,18 @@ var fs = require('graceful-fs')
 function extractPath (path, cmdshimContents) {
   if (/[.]cmd$/.test(path)) {
     return extractPathFromCmd(cmdshimContents)
+  } else if (/[.]ps1$/.test(path)) {
+    return extractPathFromPowershell(cmdshimContents)
   } else {
     return extractPathFromCygwin(cmdshimContents)
   }
 }
 
+function extractPathFromPowershell (cmdshimContents) {
+  var matches = cmdshimContents.match(/"[$]basedir[/]([^"]+?)"\s+[$]args/)
+  return matches && matches[1]
+}
+
 function extractPathFromCmd (cmdshimContents) {
   var matches = cmdshimContents.match(/"%(?:~dp0|dp0%)\\([^"]+?)"\s+%[*]/)
   return matches && matches[1]

test/integration.js

@@ -8,8 +8,10 @@ var readCmdShim = require('../index.js')
 var workDir = path.join(__dirname, path.basename(__filename, '.js'))
 var testShbang = path.join(workDir, 'test-shbang')
 var testShbangCmd = testShbang + '.cmd'
+var testShbangPowershell = testShbang + '.ps1'
 var testShim = path.join(workDir, 'test')
 var testShimCmd = testShim + '.cmd'
+var testShimPowershell = testShim + '.ps1'
 
 test('setup', function (t) {
   rimraf.sync(workDir)
@@ -88,6 +90,38 @@ test('sync-read-shbang-cygwin', function (t) {
   t.done()
 })
 
+test('async-read-no-shbang-powershell', function (t) {
+  t.plan(2)
+  readCmdShim(testShimPowershell, function (er, dest) {
+    t.error(er)
+    t.is(dest, '../integration.js')
+    t.done()
+  })
+})
+
+test('sync-read-no-shbang-powershell', function (t) {
+  t.plan(1)
+  var dest = readCmdShim.sync(testShimPowershell)
+  t.is(dest, '../integration.js')
+  t.done()
+})
+
+test('async-read-shbang-powershell', function (t) {
+  t.plan(2)
+  readCmdShim(testShbangPowershell, function (er, dest) {
+    t.error(er)
+    t.is(dest, 'test-shbang.js')
+    t.done()
+  })
+})
+
+test('sync-read-shbang-powershell', function (t) {
+  t.plan(1)
+  var dest = readCmdShim.sync(testShbangPowershell)
+  t.is(dest, 'test-shbang.js')
+  t.done()
+})
+
 test('async-read-dir', function (t) {
   t.plan(2)
   readCmdShim(workDir, function (er) {