diff --git a/range.ts b/range.ts
new file mode 100644
index 0000000..30bfd93
--- /dev/null
+++ b/range.ts
@@ -0,0 +1,12 @@
+function validRange (range: any) {
+    return range.min <= range.middle && range.middle <= range.max;
+}
+
+const range = {
+    min: 5,
+    middle: 10,    // TSLint will warn about unsorted keys here
+    max: 20
+};
+
+console.log(validRange(range));
+