From 5937ffdf25830739b8e0eae6095fca3bdc132605 Mon Sep 17 00:00:00 2001
From: Arpad Borsos <arpad.borsos@googlemail.com>
Date: Wed, 11 Mar 2020 16:40:51 +0100
Subject: [PATCH] Add constructor functions for {Symbol,Node}Links (#36845)

Using a constructor function like this can help node better optimize
object allocation. This improves memory usage when compiling
`src/compiler` from **277M** to **270M**, a nice ~3% win.
---
 src/compiler/checker.ts | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index f4ec3e8bf66..c32801ac5f5 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -242,6 +242,13 @@ namespace ts {
         ExportNamespace = 1 << 2,
     }
 
+    function SymbolLinks(this: SymbolLinks) {
+    }
+
+    function NodeLinks(this: NodeLinks) {
+        this.flags = 0;
+    }
+
     export function getNodeId(node: Node): number {
         if (!node.id) {
             node.id = nextNodeId;
@@ -1271,12 +1278,12 @@ namespace ts {
         function getSymbolLinks(symbol: Symbol): SymbolLinks {
             if (symbol.flags & SymbolFlags.Transient) return <TransientSymbol>symbol;
             const id = getSymbolId(symbol);
-            return symbolLinks[id] || (symbolLinks[id] = {});
+            return symbolLinks[id] || (symbolLinks[id] = new (<any>SymbolLinks)());
         }
 
         function getNodeLinks(node: Node): NodeLinks {
             const nodeId = getNodeId(node);
-            return nodeLinks[nodeId] || (nodeLinks[nodeId] = { flags: 0 } as NodeLinks);
+            return nodeLinks[nodeId] || (nodeLinks[nodeId] = new (<any>NodeLinks)());
         }
 
         function isGlobalSourceFile(node: Node) {