Spreadsheet: Add Range(s).at(ix)

Base/res/js/Spreadsheet/runtime.js

@@ -147,6 +147,18 @@ class Ranges {
         }
     }
 
+    at(wantedIx) {
+        let ix = 0;
+        let found = null;
+        this.forEach(cell => {
+            if (ix++ === wantedIx) {
+                found = cell;
+                return Break;
+            }
+        });
+        return found;
+    }
+
     union(other, direction = "right") {
         if (direction === "left") {
             if (other instanceof Ranges) return Ranges.from(...other.ranges, ...this.ranges);
@@ -213,6 +225,18 @@ class Range {
         }
     }
 
+    at(wantedIx) {
+        let ix = 0;
+        let found = null;
+        this.forEach(cell => {
+            if (ix++ === wantedIx) {
+                found = cell;
+                return Break;
+            }
+        });
+        return found;
+    }
+
     union(other) {
         if (other instanceof Ranges) return other.union(this, "left");
 

Userland/Applications/Spreadsheet/Tests/basic.js

@@ -108,4 +108,17 @@ describe("Range", () => {
         expect(R`A0:A25`.first().name).toEqual("A0");
         expect(R`A2:A25`.first().name).toEqual("A2");
     });
+
+    test("Range#at", () => {
+        const workbook = createWorkbook();
+        const sheet = createSheet(workbook, "Sheet 1");
+        sheet.makeCurrent();
+        let i = 0;
+        for (const col of ["A", "B"])
+            for (const row of [0, 1, 2]) sheet.setCell(col, row, Math.pow(i++, 2));
+
+        sheet.focusCell("A", 0);
+        expect(R`A0:A2`.at(2)).toEqual("A2");
+        expect(Ranges.from(R`A0:A2`, R`B0:B2`).at(5)).toEqual("B2");
+    });
 });