Spreadsheet: Add CommonRange#unique()

Base/res/js/Spreadsheet/runtime.js

@@ -197,6 +197,19 @@ class CommonRange {
         });
         return new SplitRange(cells);
     }
+
+    unique() {
+        const cells = [];
+        const values = new Set();
+        this.forEach(cell => {
+            const value = cell.value();
+            if (!values.has(value)) {
+                values.add(value);
+                cells.push(cell);
+            }
+        });
+        return new SplitRange(cells);
+    }
 }
 
 class SplitRange extends CommonRange {

Userland/Applications/Spreadsheet/Tests/basic.js

@@ -198,6 +198,21 @@ describe("SplitRange", () => {
         expect(numericResolve(range)).toEqual([1, 3, 1, 9]);
         expect(count(range)).toEqual(4);
     });
+
+    test("Range#unique => SplitRange", () => {
+        makeSheet();
+
+        const origRange = R`A0:B`;
+        const uniqueRange = origRange.unique();
+        expect(uniqueRange.toString()).toEqual(
+            'SplitRange.fromNames("A0", "A1", "A2", "B1", "B2")'
+        );
+
+        const uniqueCount = count(uniqueRange);
+        // We expect that making a set (unique array) of the original range should equal the length of our unique range
+        expect(new Set(resolve(origRange)).size).toEqual(uniqueCount);
+        expect(uniqueCount).toEqual(5);
+    });
 });
 
 describe("R function", () => {