diff --git a/cmd/tsconnect/wasm/wasm_js.go b/cmd/tsconnect/wasm/wasm_js.go
index 2744eeb34..c3319a873 100644
--- a/cmd/tsconnect/wasm/wasm_js.go
+++ b/cmd/tsconnect/wasm/wasm_js.go
@@ -1393,7 +1393,7 @@ func (i *jsIPN) setServices(jsServices js.Value) js.Value {
 // userServicesFromView converts a hostinfo services slice to jsService entries,
 // filtering out internal peerapi protocol entries (already reflected in peerAPIURL).
 func userServicesFromView(svcs views.Slice[tailcfg.Service]) []jsService {
-	var out []jsService
+	out := make([]jsService, 0, svcs.Len())
 	for _, s := range svcs.All() {
 		switch s.Proto {
 		case tailcfg.PeerAPI4, tailcfg.PeerAPI6, tailcfg.PeerAPIDNS:
@@ -1652,7 +1652,7 @@ type jsNetMapNode struct {
 	MachineKey string      `json:"machineKey"`
 	NodeKey    string      `json:"nodeKey"`
 	PeerAPIURL string      `json:"peerAPIURL,omitempty"`
-	Services   []jsService `json:"services,omitempty"`
+	Services   []jsService `json:"services"`
 }
 
 type jsNetMapSelfNode struct {