feat(dotenv): support --dotenv option

if given, it will load values from a .env file in your project, if one exists.

BREAKING CHANGE: defaultenv will now error out if one of the files in the arguments doesn't exist.

.env

@@ -0,0 +1 @@
+FOO=gloob

lib/index.js

@@ -10,6 +10,10 @@ function defaultEnv(envFiles, options) {
   options = options || {}
   var setvars = {}
   var key
+  if (options.dotenv) {
+    var parsed = dotenv.config().parsed
+    for (key in parsed) setvars[key] = parsed[key]
+  }
   for (var i = 0; i < envFiles.length; i++) {
     var file = envFiles[i]
     var defaultValues
@@ -18,6 +22,11 @@ function defaultEnv(envFiles, options) {
       if (!(defaultValues instanceof Object)) {
         throw new Error(file + ' is invalid; it should export an object, got ' + defaultValues + ' instead')
       }
+      for (key in defaultValues) {
+        if (typeof defaultValues[key] !== 'string') {
+          throw new Error(file + ' is invalid; value for ' + key + ' should be a string, got ' + defaultValues[key] + ' instead')
+        }
+      }
     } else {
       defaultValues = dotenv.parse(fs.readFileSync(file, 'utf8'))
     }
@@ -84,6 +93,7 @@ if (!module.parent) {
   }
 
   var options = {
+    dotenv: myArgs.indexOf('--dotenv') >= 0,
     force: myArgs.indexOf('-f') >= 0 || myArgs.indexOf('--force') >= 0,
     print: myArgs.indexOf('-p') >= 0 || myArgs.indexOf('--print') >= 0,
   }

lib/usage.txt

@@ -9,3 +9,6 @@ OPTIONS
   -f, --force             overwrite existing values for environment variables
                           (by default, existing values will be preserved)
 
+  --dotenv                also loads variables from a .env file in the root directory
+                          of your project
+

test/index.js

@@ -176,5 +176,16 @@ describe('defaultenv', function () {
       done()
     })
   })
+  it("loads .env when --dotenv option is given", function (done) {
+    var command = process.argv[0] + ' ' +
+      'lib/index.js --dotenv test/foo.env ' +
+      process.argv[0] + " -p 'process.env.FOO'"
+    exec(command, {
+      cwd: root,
+    }, function (error, stdout) {
+      expect(stdout.trim()).to.equal('gloob')
+      done()
+    })
+  })
 })