pkgs: add writeJS{,Bin}

ci.nix

@@ -18,6 +18,7 @@ in
     bash = writeTest "bash features" simples.bash;
     dash = writeTest "dash features" simples.dash;
     haskell = writeTest "Rolf" simples.haskell;
+    js = writeTest "function add(n,d){return n+d}" simples.js;
     perl = writeTest "Howdy!" simples.perl;
     python2 = writeTest "['some', 'random', 'variables']" simples.python2;
     python3 = writeTest "['some', 'random', 'variables']" simples.python3;

examples/hello_world.nix

@@ -18,6 +18,9 @@ in {
     main = do
       putStrLn "hello world"
   '';
+  js = pkgs.writeJS "hello-world" {} ''
+    console.log("hello world")
+  '';
   perl = pkgs.writePerl "hello-world" {} ''
     print "hello world\n";
   '';

examples/simple.nix

@@ -14,6 +14,12 @@ in {
     main :: IO ()
     main = print Rolf
   '';
+  js = pkgs.writeJS "example-js" { deps = [ pkgs.nodePackages.uglify-js ]; } ''
+    var UglifyJS = require("uglify-js");
+    var code = "function add(first, second) { return first + second; }";
+    var result = UglifyJS.minify(code);
+    console.log(result.code);
+  '';
   perl = pkgs.writePerl "simple.pl" { deps = [ pkgs.perlPackages.boolean ]; } ''
     use boolean;
     print "Howdy!\n" if true;

pkgs/default.nix

@@ -297,6 +297,23 @@ pkgs: oldpkgs: {
       };
     };
 
+  writeJS = name: { deps ? [] }: text:
+  let
+    node-env = pkgs.buildEnv {
+      name = "node";
+      paths = deps;
+      pathsToLink = [
+        "/lib/node_modules"
+      ];
+    };
+  in pkgs.writeDash name ''
+    export NODE_PATH=${node-env}/lib/node_modules
+    exec ${pkgs.nodejs}/bin/node ${pkgs.writeText "js" text}
+  '';
+
+  writeJSBin = name:
+    pkgs.writeJS "/bin/${name}";
+
   writeJSON = name: value: pkgs.runCommand name {
     json = toJSON value;
     passAsFile = [ "json" ];