add util.ts for sharing common functions between frontend and backend

src/util.ts

@@ -0,0 +1,31 @@
+// Common Util for frontend and backend
+// Backend uses the compiled file util.js
+// Frontend uses util.ts
+// Need to run "tsc" to compile if there are any changes.
+
+export const DOWN = 0;
+export const UP = 1;
+export const PENDING = 2;
+
+export function sleep(ms) {
+    return new Promise(resolve => setTimeout(resolve, ms));
+}
+
+/**
+ * PHP's ucfirst
+ * @param str
+ */
+export function ucfirst(str) {
+    if (! str) {
+        return str;
+    }
+
+    const firstLetter = str.substr(0, 1);
+    return firstLetter.toUpperCase() + str.substr(1);
+}
+
+export function debug(msg) {
+    if (process.env.NODE_ENV === "development") {
+        console.log(msg)
+    }
+}