feat: Introduce optional limit for countPathsToRoot

Author: darscan

src/core/dep-graph.ts

@@ -149,16 +149,23 @@ class DepGraphImpl implements types.DepGraphInternal {
     return pathsToRoot.sort((a, b) => a.length - b.length);
   }
 
-  public countPathsToRoot(pkg: types.Pkg): number {
+  public countPathsToRoot(pkg: types.Pkg, opts?: { limit?: number }): number {
     let count = 0;
+    const limit = opts?.limit;
     for (const nodeId of this.getPkgNodeIds(pkg)) {
       if (this._countNodePathsToRootCache.has(nodeId)) {
         count += this._countNodePathsToRootCache.get(nodeId)!;
       } else {
-        const c = this.countNodePathsToRoot(nodeId);
-        this._countNodePathsToRootCache.set(nodeId, c);
+        const c = this.countNodePathsToRoot(nodeId, limit);
+        // don't cache if a limit was supplied
+        if (!limit) {
+          this._countNodePathsToRootCache.set(nodeId, c);
+        }
         count += c;
       }
+      if (limit && count >= limit) {
+        return limit;
+      }
     }
     return count;
   }
@@ -372,15 +379,22 @@ class DepGraphImpl implements types.DepGraphInternal {
     return allPaths;
   }
 
-  private countNodePathsToRoot(nodeId: string, visited: string[] = []): number {
+  private countNodePathsToRoot(
+    nodeId: string,
+    limit = 0,
+    count = 0,
+    visited: string[] = [],
+  ): number {
     if (nodeId === this._rootNodeId) {
-      return 1;
+      return count + 1;
     }
     visited = visited.concat(nodeId);
-    let count = 0;
     for (const parentNodeId of this.getNodeParentsNodeIds(nodeId)) {
       if (!visited.includes(parentNodeId)) {
-        count += this.countNodePathsToRoot(parentNodeId, visited);
+        count = this.countNodePathsToRoot(parentNodeId, limit, count, visited);
+        if (limit && count >= limit) {
+          return limit;
+        }
       }
     }
     return count;

src/core/types.ts

@@ -100,7 +100,7 @@ export interface DepGraph {
   pkgPathsToRoot(pkg: Pkg, opts?: { limit?: number }): PkgInfo[][];
   isTransitive(pkg: Pkg): boolean;
   directDepsLeadingTo(pkg: Pkg): PkgInfo[];
-  countPathsToRoot(pkg: Pkg): number;
+  countPathsToRoot(pkg: Pkg, opts?: { limit?: number }): number;
   equals(other: DepGraph, options?: { compareRoot?: boolean }): boolean;
 }