fix rank

src/model/RankColumn.ts

@@ -43,8 +43,8 @@ export default class RankColumn extends Column {
     let offset = 0;
     for (const group of groups) {
       const rank = group.index2pos[row.i];
-      if (typeof rank === 'number' && !isNaN(rank)) {
-        return rank + 1 + offset; // starting with 1
+      if (typeof rank === 'number' && !isNaN(rank) && rank > 0) {
+        return rank + offset;
       }
       offset += group.order.length;
     }

src/provider/LocalDataProvider.ts

@@ -173,7 +173,8 @@ export default class LocalDataProvider extends ACommonDataProvider {
       // initial no sorting required just index mapping
       const order = chooseByLength(this._data.length);
       order.set(range(this._data.length));
-      const index2pos = order.slice();
+      const index2pos = chooseByLength(this._data.length);
+      index2pos.set(range(1, this._data.length + 1));
       return [Object.assign({order, index2pos}, defaultGroup)];
     }
 

src/provider/sort.ts

@@ -86,7 +86,7 @@ function sort2indices(arr: {i: number}[], rawLength: number) {
   for (let i = 0; i < arr.length; ++i) {
     const ri = arr[i].i;
     order[i] = ri;
-    index2pos[ri] = i;
+    index2pos[ri] = i + 1; // shift by one
   }
   return {order, index2pos};
 }