add tree benchmark

.gitignore

@@ -10,3 +10,5 @@ debug.test
 .idea/
 /web/node_modules/
 /web/public/
+*.prof
+*.test

app/rest/format/tree.go

@@ -22,10 +22,11 @@ type Node struct {
 func MakeTree(comments []store.Comment, sortType string) *Tree {
 	res := Tree{}
 
-	repComments := res.filter(comments, "")
-	for _, rc := range repComments {
+	topComments := res.filter(comments, "")
+	res.Nodes = make([]*Node, len(topComments))
+	for i, rc := range topComments {
 		node := Node{Comment: rc}
-		res.Nodes = append(res.Nodes, res.proc(comments, &node, rc.ID))
+		res.Nodes[i] = res.proc(comments, &node, rc.ID)
 	}
 
 	res.sortNodes(sortType)
@@ -49,6 +50,7 @@ func (t *Tree) proc(comments []store.Comment, node *Node, parentID string) *Node
 
 // filter returns comments for parentID
 func (t *Tree) filter(comments []store.Comment, parentID string) (f []store.Comment) {
+
 	for _, c := range comments {
 		if c.ParentID == parentID {
 			f = append(f, c)

app/rest/format/tree_test.go

@@ -3,6 +3,7 @@ package format
 import (
 	"bytes"
 	"encoding/json"
+	"io/ioutil"
 	"testing"
 	"time"
 
@@ -39,6 +40,19 @@ func TestStore_MakeTree(t *testing.T) {
 	// t.Log(string(buf.Bytes()))
 }
 
+func BenchmarkTree(b *testing.B) {
+	comments := []store.Comment{}
+	data, err := ioutil.ReadFile("testfile.json")
+	assert.Nil(b, err)
+	err = json.Unmarshal(data, &comments)
+	assert.Nil(b, err)
+
+	for i := 0; i < b.N; i++ {
+		res := MakeTree(comments, "time")
+		assert.NotNil(b, res)
+	}
+}
+
 const expJSON = `{
   "comments": [
     {