Understanding promises

js/rate-service-mock.js

@@ -0,0 +1,20 @@
+let rates = [
+    {
+        "name": "30 years fixed",
+        "rate": "13",
+        "years": "30"
+    },
+    {
+        "name": "20 years fixed",
+        "rate": "2.8",
+        "years": "20"
+    }
+];
+
+export let findAll = () => new Promise((resolve, reject) => {
+    if (rates) {
+        resolve(rates);
+    } else {
+        reject("No rates");
+    }
+});