perf: reduce linear search on list traversing

babel · Nov 3, 2020 · 04cba55 · 04cba55
1 parent 487f82e
commit 04cba55
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Showing 3 changed files with 10 additions and 18 deletions.
diff --git a/packages/babel-traverse/src/context.js b/packages/babel-traverse/src/context.js
@@ -95,7 +95,7 @@ export default class TraversalContext {
     this.queue = queue;
     this.priorityQueue = [];
 
-    const visited = [];
+    const visited = new WeakSet();
     let stop = false;
 
     // visit the queue
@@ -120,8 +120,9 @@ export default class TraversalContext {
       }
 
       // ensure we don't visit the same node twice
-      if (visited.indexOf(path.node) >= 0) continue;
-      visited.push(path.node);
+      const { node } = path;
+      if (visited.has(node)) continue;
+      if (node) visited.add(node);
 
       if (path.visit()) {
         stop = true;

diff --git a/packages/babel-traverse/src/path/index.js b/packages/babel-traverse/src/path/index.js
@@ -67,24 +67,16 @@ export default class NodePath {
 
     const targetNode = container[key];
 
-    const paths = pathCache.get(parent) || [];
-    if (!pathCache.has(parent)) {
+    let paths = pathCache.get(parent);
+    if (!paths) {
+      paths = new Map();
       pathCache.set(parent, paths);
     }
 
-    let path;
-
-    for (let i = 0; i < paths.length; i++) {
-      const pathCheck = paths[i];
-      if (pathCheck.node === targetNode) {
-        path = pathCheck;
-        break;
-      }
-    }
-
+    let path = paths.get(targetNode);
     if (!path) {
       path = new NodePath(hub, parent);
-      paths.push(path);
+      if (targetNode) paths.set(targetNode, path);
     }
 
     path.setup(parentPath, container, listKey, key);

diff --git a/packages/babel-traverse/src/path/modification.js b/packages/babel-traverse/src/path/modification.js
@@ -163,8 +163,7 @@ export function updateSiblingKeys(fromIndex, incrementBy) {
   if (!this.parent) return;
 
   const paths = pathCache.get(this.parent);
-  for (let i = 0; i < paths.length; i++) {
-    const path = paths[i];
+  for (const [, path] of paths) {
     if (path.key >= fromIndex) {
       path.key += incrementBy;
     }