run npm install to generate a package lock

node_modules/function-once/src/index.ts

@@ -0,0 +1,26 @@
+
+/* MAIN */
+
+const once = <T> ( fn: (() => T) ): (() => T) => {
+
+  let called = false;
+  let result: T;
+
+  return (): T => {
+
+    if ( !called ) {
+
+      called = true;
+      result = fn ();
+
+    }
+
+    return result;
+
+  };
+
+};
+
+/* EXPORT */
+
+export default once;