move from npmlock2nix to importNpmLock

nix/overlay.nix

@@ -0,0 +1,3 @@
+prev: final: {
+  map-boundaries = final.callPackage ./package.nix {};
+}

nix/package.nix

@@ -0,0 +1,20 @@
+{
+  buildNpmPackage,
+  importNpmLock,
+  lib,
+}: let
+  src = lib.sources.sourceByRegex (lib.cleanSource ../.) ["package.*" "src(/.*)?" "tsconfig.json" ".*.config.js"];
+in buildNpmPackage {
+  pname = "mapboundaries";
+  version = "0.1.0";
+
+  inherit src;
+
+  npmDeps = importNpmLock {
+    npmRoot = src;
+  };
+
+  npmConfigHook = importNpmLock.npmConfigHook;
+
+  installPhase = "cp -r build $out";
+}