create script for builing npm package

.gitignore

@@ -0,0 +1 @@
+npm/*

build-for-npm.ts

@@ -0,0 +1,17 @@
+import { build, emptyDir } from "https://deno.land/x/dnt@0.40.0/mod.ts";
+
+await emptyDir("./npm");
+
+await build({
+  entryPoints: ["./mod.ts"],
+  outDir: "./npm",
+  shims: {
+    // see JS docs for overview and more options
+    deno: true,
+  },
+  package: {
+    // package.json properties
+    name: "result",
+    version: Deno.args[0],
+  },
+});