From 6016c7e6d94cff037dc5c689c188ca8c781fe263 Mon Sep 17 00:00:00 2001
From: Alexander Wang <alex@terrastruct.com>
Date: Sat, 20 Jan 2024 11:13:34 -0800
Subject: [PATCH] getparentid

---
 d2js/js.go | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/d2js/js.go b/d2js/js.go
index 7c6a0c880..a642ed625 100644
--- a/d2js/js.go
+++ b/d2js/js.go
@@ -20,6 +20,7 @@ import (
 )
 
 func main() {
+	js.Global().Set("d2GetParentID", js.FuncOf(jsGetParentID))
 	js.Global().Set("d2GetObjOrder", js.FuncOf(jsGetObjOrder))
 	js.Global().Set("d2GetRefRanges", js.FuncOf(jsGetRefRanges))
 	js.Global().Set("d2Compile", js.FuncOf(jsCompile))
@@ -64,6 +65,26 @@ func jsGetObjOrder(this js.Value, args []js.Value) interface{} {
 	return string(str)
 }
 
+func jsGetParentID(this js.Value, args []js.Value) interface{} {
+	id := args[0].String()
+
+	mk, _ := d2parser.ParseMapKey(id)
+
+	if len(mk.Edges) > 0 {
+		return ""
+	}
+
+	if mk.Key != nil {
+		if len(mk.Key.Path) == 1 {
+			return "root"
+		}
+		mk.Key.Path = mk.Key.Path[:len(mk.Key.Path)-1]
+		return strings.Join(mk.Key.IDA(), ".")
+	}
+
+	return ""
+}
+
 type jsRefRanges struct {
 	Ranges     []d2ast.Range `json:"ranges"`
 	ParseError string        `json:"parseError"`