install: fix max callstack exceeded loops with links

PR-URL: https://github.com/npm/npm/pull/17652
Credit: @iarna
Reviewed-By: @zkat

1 files changed, 7 insertions, 7 deletions

diff --git a/lib/ls.js b/lib/ls.js
index 67f09485f..27c8ada8a 100644
--- a/lib/ls.js
+++ b/lib/ls.js
@@ -87,13 +87,13 @@ var lsFromTree = ls.fromTree = function (dir, physicalTree, args, silent, cb) {
   var json = npm.config.get('json')
   var out
   if (json) {
-    var seen = []
+    var seen = new Set()
     var d = long ? unlooped : lite
     // the raw data can be circular
     out = JSON.stringify(d, function (k, o) {
       if (typeof o === 'object') {
-        if (inList(seen, o)) return '[Circular]'
-        seen.push(o)
+        if (seen.has(o)) return '[Circular]'
+        seen.add(o)
       }
       return o
     }, 2)
@@ -255,8 +255,8 @@ function getLite (data, noname, depth) {
 
 function unloop (root) {
   var queue = [root]
-  var seen = {}
-  seen[root.path] = true
+  var seen = new Set()
+  seen.add(root)
 
   while (queue.length) {
     var current = queue.shift()
@@ -264,13 +264,13 @@ function unloop (root) {
     Object.keys(deps).forEach(function (d) {
       var dep = deps[d]
       if (dep.missing && !dep.dependencies) return
-      if (dep.path && seen[dep.path]) {
+      if (dep.path && seen.has(dep)) {
         dep = deps[d] = Object.assign({}, dep)
         dep.dependencies = {}
         dep._deduped = path.relative(root.path, dep.path).replace(/node_modules\//g, '')
         return
       }
-      seen[dep.path] = true
+      seen.add(dep)
       queue.push(dep)
     })
   }