add jspm-generator function

Author: fusionstrings

js/importmap-generator.js

@@ -0,0 +1,21 @@
+import { Generator } from "https://cdn.jsdelivr.net/gh/fusionstrings/dependencies@c59ae9dde8d5d339b3c0433d4b4f46e72739fafe/dist/deno/jspm.js";
+
+async function main(subpath = "./js/main.js") {
+    const generator = new Generator();
+
+    await generator.install([
+        {
+            alias: "@fusionstrings/river",
+            target: "./",
+            subpath,
+        },
+    ]);
+    const importMap = JSON.stringify(generator.getMap(), null, 2);
+    return importMap;
+}
+
+if (import.meta.main) {
+    main();
+}
+
+export { main }