refactor recursion to loop

Author: Milan Meva

lib/commands/ls.js

@@ -58,7 +58,7 @@ class LS extends ArboristWorkspaceCmd {
     const unicode = this.npm.config.get('unicode')
     const packageLockOnly = this.npm.config.get('package-lock-only')
     const workspacesEnabled = this.npm.flatOptions.workspacesEnabled
-    const includeWorkspaceRoot = this.npm.flatOptions.includeWorkspaceRoot
+    const includeWorkspaceRoot = this.npm.config.get('include-workspace-root')
 
     const path = global ? resolve(this.npm.globalDir, '..') : this.npm.prefix
 
@@ -246,81 +246,100 @@ const exploreDependencyGraph = ({
   configs,
   seenNodes,
   problems,
-  cache = new Map(),
-  traversePathMap = new Map(),
 }) => {
   const { json, parseable, depthToPrint, args } = configs
 
-  // cahce is for already visited nodes results
-  // if the node is already seen, we can return it from cache
-  if (cache.has(node.path)) {
-    return cache.get(node.path)
-  }
-
-  const currentNodeResult = visit(node, seenNodes, problems, configs)
-
-  // how the this node is explored
-  // so if the explored path contains this node again then it's a cycle
-  // and we don't want to explore it again
-  // Track the path of pkgids to detect cycles efficiently
-  const parentTraversePath = traversePathMap.get(currentNodeResult[_parent]) || []
-  const isCircular = parentTraversePath.includes(node.pkgid)
-  const currentPath = [...parentTraversePath, node.pkgid]
-  traversePathMap.set(currentNodeResult, currentPath)
-
-  // we want to start using cache after node is identified as a deduped
-  if (node[_dedupe]) {
-    cache.set(node.path, currentNodeResult)
-  }
-
-  const currentDepth = node.isWorkspace ? 0 : node[_depth]
-  const shouldSkipChildren =
-       (currentDepth > depthToPrint)
-
-  // Get children of current node
-  const children = isCircular || shouldSkipChildren || !currentNodeResult
-    ? []
-    : getChildren(node, wsNodes, configs)
-
-  // Recurse on each child node
-  for (const child of children) {
-  // _parent is going to be a ref to a traversed node (returned from
-  // getHumanOutputItem, getJsonOutputItem, etc) so that we have an easy
-  // shortcut to place new nodes in their right place during tree traversal
-    child[_parent] = currentNodeResult
-    // _include is the property that allow us to filter based on position args
-    // e.g: `npm ls foo`, `npm ls simple-output@2`
-    // _filteredBy is used to apply extra color info to the item that
-    // was used in args in order to filter
-    child[_filteredBy] = child[_include] =
-    filterByPositionalArgs(args, { node: child })
-    // _depth keeps track of how many levels deep tree traversal currently is
-    // so that we can `npm ls --depth=1`
-    child[_depth] = currentDepth + 1
-
-    const childResult = exploreDependencyGraph({
-      node: child,
-      wsNodes,
-      configs,
-      seenNodes,
-      problems,
-      cache,
-      traversePathMap,
-    })
-    // include current node if any of its children are included
-    currentNodeResult[_include] = currentNodeResult[_include] || childResult[_include]
-
-    if (childResult[_include] && !parseable) {
-      if (json) {
-        currentNodeResult.dependencies = currentNodeResult.dependencies || {}
-        currentNodeResult.dependencies[childResult[_name]] = childResult
-      } else {
-        currentNodeResult.nodes.push(childResult)
+  // Stack for iterative traversal
+  const stack = []
+  // Map to store results for each node
+  const results = new WeakMap()
+
+  // Cache for deduped nodes
+  const cache = new Map()
+
+  // Initialize stack with the root node
+  stack.push({
+    node,
+    parent: null,
+    parentTraversePath: [],
+    state: 'not-processed', // 'enter' or 'exit'
+  })
+
+  while (stack.length > 0) {
+    const current = stack[stack.length - 1]
+    const { node: currentNode, parentTraversePath, state, parent } = current
+
+    const currentDepth = currentNode.isWorkspace ? 0 : currentNode[_depth]
+    const shouldSkipChildren = currentDepth > depthToPrint
+
+    currentNode[_parent] = parent
+    currentNode[_filteredBy] = currentNode[_include] =
+          filterByPositionalArgs(args, { node: currentNode })
+
+    // Cycle detection
+    const isCircular = parentTraversePath.includes(currentNode.path)
+    const currentPath = [...parentTraversePath, currentNode.path]
+
+    if (state === 'not-processed') {
+      // Check cache
+      if (cache.has(currentNode.path)) {
+        results.set(currentNode, cache.get(currentNode.path))
+        stack.pop()
+        continue
+      }
+
+      // Visit node
+      const currentNodeResult = visit(currentNode, seenNodes, problems, configs)
+
+      // Get children if not circular/shouldn't skip
+      let children = []
+      if (!isCircular && !shouldSkipChildren) {
+        children = getChildren(currentNode, wsNodes, configs)
+      }
+
+      // Push children onto stack
+      for (let i = children.length - 1; i >= 0; i--) {
+        const child = children[i]
+        child[_depth] = currentDepth + 1
+        stack.push({
+          node: child,
+          parent: currentNodeResult,
+          parentTraversePath: currentPath,
+          state: 'not-processed',
+        })
+      }
+      // since this node is processed
+      current.state = 'processed' // next state will be 'processed'
+      current.currentNodeResult = currentNodeResult
+      current.children = children
+    }
+    if (state === 'processed') {
+      // Collect child results
+      const { currentNodeResult, children } = current
+
+      for (const child of children) {
+        const childResult = results.get(child)
+        currentNodeResult[_include] = currentNodeResult[_include] || childResult[_include]
+        if (childResult[_include] && !parseable) {
+          if (json) {
+            currentNodeResult.dependencies = currentNodeResult.dependencies || {}
+            currentNodeResult.dependencies[childResult[_name]] = childResult
+          } else {
+            currentNodeResult.nodes.push(childResult)
+          }
+        }
+      }
+
+      results.set(currentNode, currentNodeResult)
+      if (currentNode[_dedupe]) {
+        cache.set(currentNode.path, currentNodeResult)
       }
+      stack.pop()
     }
   }
 
-  return currentNodeResult
+  // Return the result for the root node
+  return results.get(node)
 }
 
 const isGitNode = (node) => {

tap-snapshots/test/lib/commands/ls.js.test.cjs

@@ -526,7 +526,7 @@ [email protected] {CWD}/prefix
 exports[`test/lib/commands/ls.js TAP ls missing package.json > should output tree missing name/version of top-level package 1`] = `
 {CWD}/prefix
 +-- [email protected] extraneous
-+-- [email protected] extraneous
++-- [email protected] deduped extraneous
 \`-- [email protected] extraneous
   \`-- [email protected] deduped extraneous
 `
@@ -672,7 +672,11 @@ [email protected] {CWD}/prefix
 |   \`-- [email protected] deduped invalid: "^2.0.0" from the root project
 +-- [email protected] extraneous
 | \`-- [email protected] deduped invalid: "^1.2.3" from the root project, "^2.0.0" from node_modules/cat, "2.x" from node_modules/chai
-|   \`-- [email protected] deduped invalid: "^2.0.0" from the root project
+|   \`-- [email protected] invalid: "^2.0.0" from the root project
+|     \`-- [email protected] invalid: "^1.2.3" from the root project, "^2.0.0" from node_modules/cat
+|       \`-- [email protected] deduped invalid: "^2.0.0" from the root project
 \`-- [email protected] deduped invalid: "^1.2.3" from the root project, "^2.0.0" from node_modules/cat, "2.x" from node_modules/chai
-  \`-- [email protected] deduped invalid: "^2.0.0" from the root project
+  \`-- [email protected] invalid: "^2.0.0" from the root project
+    \`-- [email protected] invalid: "^1.2.3" from the root project, "^2.0.0" from node_modules/cat
+      \`-- [email protected] deduped invalid: "^2.0.0" from the root project
 `