diff --git a/src/services/playground2.js b/src/services/playground2.js
new file mode 100644
index 0000000..ad56039
--- /dev/null
+++ b/src/services/playground2.js
@@ -0,0 +1,19 @@
+var predicates = {
+  '==': function (a, b) {
+    return a === b;
+  },
+  '>=': function (a, b) {
+    return a >= b;
+  },
+  '<': function (a, b, item) {
+    return item[a] < item[b];
+  },
+};
+let p = predicates['<'];
+let item = {
+  a: 1,
+  b: 2,
+};
+console.log(item['a'], item['b']);
+console.log(item['a'] < item['b']);
+console.log(p('a', 'b', item));