Reduce linear search on list traversing (#12302)

* perf: reduce linear search on list traversing

* fix: remove parent cache when replacing node

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;

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);

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;
     }

packages/babel-traverse/src/path/removal.js

@@ -1,6 +1,7 @@
 // This file contains methods responsible for removing a node.
 
 import { hooks } from "./lib/removal-hooks";
+import { path as pathCache } from "../cache";
 import { REMOVED, SHOULD_SKIP } from "./index";
 
 export function remove() {
@@ -44,6 +45,7 @@ export function _remove() {
 export function _markRemoved() {
   // this.shouldSkip = true; this.removed = true;
   this._traverseFlags |= SHOULD_SKIP | REMOVED;
+  if (this.parent) pathCache.get(this.parent).delete(this.node);
   this.node = null;
 }
 

packages/babel-traverse/src/path/replacement.js

@@ -3,6 +3,7 @@
 import { codeFrameColumns } from "@babel/code-frame";
 import traverse from "../index";
 import NodePath from "./index";
+import { path as pathCache } from "../cache";
 import { parse } from "@babel/parser";
 import * as t from "@babel/types";
 
@@ -49,6 +50,7 @@ export function replaceWithMultiple(nodes: Array<Object>) {
   nodes = this._verifyNodeList(nodes);
   t.inheritLeadingComments(nodes[0], this.node);
   t.inheritTrailingComments(nodes[nodes.length - 1], this.node);
+  pathCache.get(this.parent).delete(this.node);
   this.node = this.container[this.key] = null;
   const paths = this.insertAfter(nodes);