Best results yet

app/assets/javascripts/discourse/app/lib/dag-map.js

@@ -6,7 +6,6 @@ export default class DAGMap {
   #nodes = new Map();
   #incomingEdges = new Map();
   #outgoingEdges = new Map();
-
   #staged = new Map();
 
   add(key, value, { before, after } = {}) {
@@ -37,25 +36,27 @@ export default class DAGMap {
   }
 
   sort() {
-    const firstPass = this.#topologicalSort(
+    let result = this.#topologicalSort(
       this.#incomingEdges,
       this.#outgoingEdges
     );
 
     if (this.#staged.size === 0) {
-      return firstPass;
+      return result;
     }
 
     const secondPassIncomingEdges = new Map(this.#incomingEdges.entries());
     const secondPassOutgoingEdges = new Map(this.#outgoingEdges.entries());
 
+    result = result.filter((key) => !this.#staged.has(key));
+
     Array.from(this.#staged.entries()).forEach(([key, beforeConstraints]) => {
       // we need to get the leftmost node before the constraints
       let leftMostNode = null;
 
       beforeConstraints.forEach((b) => {
         this.#addEdge(key, b, secondPassIncomingEdges, secondPassOutgoingEdges);
-        const bIndex = firstPass.indexOf(b);
+        const bIndex = result.indexOf(b);
 
         if (leftMostNode === null || leftMostNode > bIndex) {
           leftMostNode = bIndex - 1;
@@ -66,17 +67,17 @@ export default class DAGMap {
       //   "leftMostNode for",
       //   key,
       //   leftMostNode,
-      //   firstPass[leftMostNode]
+      //   result[leftMostNode]
       // );
 
       if (
         leftMostNode !== null &&
         leftMostNode >= 0 &&
-        !this.#staged.has(key)
+        !this.#staged.has(leftMostNode)
       ) {
         // this adds an additional constraint forcing the item to be placed after the leftmost node
         this.#addEdge(
-          firstPass[leftMostNode],
+          result[leftMostNode],
           key,
           secondPassIncomingEdges,
           secondPassOutgoingEdges

app/assets/javascripts/discourse/app/lib/dag.js

@@ -1,5 +1,5 @@
-import DAGMap from "dag-map";
-// import DAGMap from "discourse/lib/dag-map";
+// import DAGMap from "dag-map";
+import DAGMap from "discourse/lib/dag-map";
 import { makeArray } from "discourse-common/lib/helpers";
 import { bind } from "discourse-common/utils/decorators";
 
@@ -215,17 +215,17 @@ export default class DAG {
    */
   #addHandlingCycles(dag, key, value, before, after) {
     if (this.#throwErrorOnCycle) {
-      dag.add(key, value, before, after);
+      dag.add(key, value, { before, after });
     } else {
       try {
-        dag.add(key, value, before, after);
+        dag.add(key, value, { before, after });
       } catch (e) {
         if (e.message.match(/cycle/i)) {
           const { before: newBefore, after: newAfter } =
             this.#defaultPositionForKey(key);
 
           // if even the default position causes a cycle, an error will be thrown
-          dag.add(key, value, newBefore, newAfter);
+          dag.add(key, value, { newBefore, newAfter });
         }
       }
     }

app/assets/javascripts/discourse/tests/unit/lib/dag-map-test.js

@@ -16,6 +16,17 @@ module("Unit | Lib | DAGMap", function (hooks) {
     assert.deepEqual(sorted, ["key1", "key2", "key3"]);
   });
 
+  test("Items are positioned correctly when all items have hints", function (assert) {
+    const dagMap = new DAGMap();
+    dagMap.add("key1", null, { after: "key2" });
+    dagMap.add("key2", null, { before: "key3" });
+    dagMap.add("key3", null, { before: "key1" });
+
+    const sorted = dagMap.sort();
+
+    assert.deepEqual(sorted, ["key2", "key3", "key1"]);
+  });
+
   test("Items are positioned just after the specified item", function (assert) {
     const dagMap = new DAGMap();
     dagMap.add("key1");

app/assets/javascripts/discourse/tests/unit/lib/dag-test.js

@@ -279,7 +279,7 @@ module("Unit | Lib | DAG", function (hooks) {
     const dag = new DAG();
     dag.add("key1", "value1");
     dag.add("key2", "value2", { before: "key1" });
-    dag.add("key3", "value3");
+    dag.add("key3", "value3", { after: "key1" });
 
     dag.delete("key1");