npm
diff --git a/‎lib/install/is-only-dev.js
Copy file name to clipboardExpand all lines: lib/install/is-only-dev.js
+3-2Lines changed: 3 additions & 2 deletions b/‎lib/install/is-only-dev.js
Copy file name to clipboardExpand all lines: lib/install/is-only-dev.js
+3-2Lines changed: 3 additions & 2 deletions
diff --git a/‎lib/install/is-only-optional.js
Copy file name to clipboardExpand all lines: lib/install/is-only-optional.js
+3-2Lines changed: 3 additions & 2 deletions b/‎lib/install/is-only-optional.js
Copy file name to clipboardExpand all lines: lib/install/is-only-optional.js
+3-2Lines changed: 3 additions & 2 deletions
@@ -28,9 +28,10 @@ function andIsOnlyDev (name, seen) {
       return isDev && !isProd
     } else {
       if (seen.has(req)) return true
-      seen = new Set(seen)
       seen.add(req)
-      return isOnlyDev(req, seen)
+      const result = isOnlyDev(req, seen)
+      seen.delete(req)
+      return result
     }
   }
 }
@@ -11,11 +11,12 @@ function isOptional (node, seen) {
   if (seen.has(node) || node.requiredBy.length === 0) {
     return false
   }
-  seen = new Set(seen)
   seen.add(node)
   const swOptional = node.fromShrinkwrap && node.package._optional
-  return node.requiredBy.every(function (req) {
+  const result = node.requiredBy.every(function (req) {
     if (req.fakeChild && swOptional) return true
     return isOptDep(req, moduleName(node)) || isOptional(req, seen)
   })
+  seen.delete(node)
+  return result
 }
Original file line number	Diff line number	Diff line change
`@@ -28,9 +28,10 @@ function andIsOnlyDev (name, seen) {`
`28`	`28`	`return isDev && !isProd`
`29`	`29`	`} else {`
`30`	`30`	`if (seen.has(req)) return true`
`31`		`- seen = new Set(seen)`
`32`	`31`	`seen.add(req)`
`33`		`- return isOnlyDev(req, seen)`
	`32`	`+ const result = isOnlyDev(req, seen)`
	`33`	`+ seen.delete(req)`
	`34`	`+ return result`
`34`	`35`	`}`
`35`	`36`	`}`
`36`	`37`	`}`