1 files changed, 27 insertions, 0 deletions
diff --git a/src/utils/iterator.ts b/src/utils/iterator.ts
index fa58fc9..43437b6 100644
--- a/src/utils/iterator.ts
+++ b/src/utils/iterator.ts
@@ -50,3 +50,30 @@ export async function findMapAsync<T, R>(
 
   return await tryNext(0);
 }
+
+export function createRanges(nums: Iterable<number>): string[] {
+  const ns = new Set(nums).values().toArray().sort((
+    a,
+    b,
+  ) => a - b);
+
+  const result = [];
+  let start = ns[0];
+  let end = ns[0];
+
+  for (let i = 1; i <= ns.length; i++) {
+    if (ns[i] === end + 1) {
+      end = ns[i];
+    } else {
+      if (start === end) {
+        result.push(`${start}`);
+      } else {
+        result.push(`${start}-${end}`);
+      }
+      start = ns[i];
+      end = ns[i];
+    }
+  }
+
+  return result;
+}