Add dependency ckecking method, required for nghyd#212

src/nub.ts

@@ -578,6 +578,27 @@ export abstract class Nub extends ComputeNode implements IObservable {
         return requiredNubs;
     }
 
+    /**
+     * Returns all Nubs whose parameters or results are targettes
+     * by the given one.
+     * (used for dependencies checking at session saving time)
+     */
+    public getTargettedNubs(visited: string[] = []) {
+        const targettedNubs: Nub[] = [];
+        // prevent loops
+        if (! visited.includes(this.uid)) {
+            visited.push(this.uid);
+
+            // inspect all target Nubs
+            for (const p of this.parameterIterator) {
+                if (p.valueMode === ParamValueMode.LINK && p.isReferenceDefined()) {
+                    targettedNubs.push(p.referencedValue.nub);
+                }
+            }
+        }
+        return targettedNubs;
+    }
+
     /**
      * Returns true if
      *  - this Nub