feat(node): version mismatch color

resolves #378

docs/docs/segment-node.md

@@ -31,3 +31,8 @@ Display the currently active node version.
 - display_mode: `string` - determines when the segment is displayed
   - `always`: The segment is always displayed
   - `files`: The segment is only displayed when `*.js`, `*.ts`, or `package.json` files are present (default)
+- enable_version_mismatch: `boolean` - color the segment when the version in `.nvmrc` doesn't match the
+returned node version
+- color_background: `boolean` - color the background or foreground for `version_mismatch_color` - defaults to `false`
+- version_mismatch_color: `string` [color][colors] - the color to use for `enable_version_mismatch` - defaults to
+segment's background or foreground color

src/segment_node.go

@@ -12,7 +12,7 @@ func (n *node) init(props *properties, env environmentInfo) {
 	n.language = &language{
 		env:        env,
 		props:      props,
-		extensions: []string{"*.js", "*.ts", "package.json", ".nvm"},
+		extensions: []string{"*.js", "*.ts", "package.json", ".nvmrc"},
 		commands: []*cmd{
 			{
 				executable: "node",
@@ -30,5 +30,9 @@ func (n *node) enabled() bool {
 }
 
 func (n *node) matchesVersionFile() bool {
-	return true
+	fileVersion := n.language.env.getFileContent(".nvmrc")
+	if len(fileVersion) == 0 {
+		return true
+	}
+	return fileVersion == n.language.activeCommand.version.full
 }

src/segment_node_test.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/alecthomas/assert"
+)
+
+func TestNodeMatchesVersionFile(t *testing.T) {
+	cases := []struct {
+		Case      string
+		Expected  bool
+		RCVersion string
+		Version   string
+	}{
+		{Case: "no file context", Expected: true, RCVersion: "", Version: "durp"},
+		{Case: "version match", Expected: true, RCVersion: "durp", Version: "durp"},
+		{Case: "version mismatch", Expected: false, RCVersion: "werp", Version: "durp"},
+	}
+
+	for _, tc := range cases {
+		env := new(MockedEnvironment)
+		env.On("getFileContent", ".nvmrc").Return(tc.RCVersion)
+		node := &node{
+			language: &language{
+				env: env,
+				activeCommand: &cmd{
+					version: &version{
+						full: tc.Version,
+					},
+				},
+			},
+		}
+		assert.Equal(t, tc.Expected, node.matchesVersionFile(), tc.Case)
+	}
+}