diff --git a/default.nix b/default.nix
index 3aa4d38..96a8011 100644
--- a/default.nix
+++ b/default.nix
@@ -1,5 +1,5 @@
 { writeShellScriptBin, writeText, runCommand, writeScriptBin,
-  stdenv, fetchurl, makeWrapper, nodejs, yarn, jq }:
+  stdenv, fetchurl, makeWrapper, nodejs, yarn, jq, gnutar }:
 with stdenv.lib; let
   inherit (builtins) fromJSON toJSON split removeAttrs toFile;
 
@@ -8,18 +8,35 @@ with stdenv.lib; let
 
   depsToFetches = deps: concatMap depToFetch (attrValues deps);
 
-  depFetchOwn = { resolved, integrity, name ? null, ... }:
+  makeTarball = name: path: runCommand "${name}.tar.gz" {
+    buildInputs = [ gnutar ];
+  } ''
+    cp -R "${path}" package
+    tar -caf $out package
+  '';
+
+  depFetchOwn = args:
     let
-      ssri      = split "-" integrity;
+      uri       = args.resolved or args.version;
+      parsedURI = splitString "://" uri;
+      parsedPath= splitString "#" uri;
+      parsedFrom= splitString "#" args.from;
+      rev       = elemAt parsedPath 1;
+      ref       = if builtins.length parsedFrom > 1 then elemAt parsedFrom 1 else "master";
+      protocol  = elemAt parsedURI 0;
+      ssri      = split "-" args.integrity;
       hashType  = head ssri;
       hash      = elemAt ssri 2;
-      bname     = baseNameOf resolved;
+      bname     = baseNameOf uri;
       fname     = if hasSuffix ".tgz" bname || hasSuffix ".tar.gz" bname
                   then bname else bname + ".tgz";
-    in nameValuePair resolved {
-      inherit name bname;
-      path = fetchurl { name = fname; url = resolved; "${hashType}" = hash; };
-    };
+      path      = if hasInfix "git" protocol
+                  then makeTarball (args.name or "source") (builtins.fetchGit { url = uri; inherit ref rev; })
+                  else if args ? integrity
+                  then fetchurl { name = fname; url = uri; "${hashType}" = hash; }
+                  else throw "Unsupported dependency ${uri} (${args.name or "no name"})";
+
+    in nameValuePair uri { name = args.name or null; inherit bname path; };
 
   overrideTgz = src: runCommand "${src.name}.tgz" {} ''
     cp -r --reflink=auto ${src} ./package
@@ -31,8 +48,8 @@ with stdenv.lib; let
 
   overrideToFetch = pkg: { path = "${overrideTgz pkg}"; };
 
-  depToFetch = args @ { resolved ? null, dependencies ? {}, ... }:
-    (optional (resolved != null) (depFetchOwn args)) ++ (depsToFetches dependencies);
+  depToFetch = args @ { dependencies ? {}, ... }:
+    (optional ((args ? resolved || args ? version) && (args ? integrity || args ? from)) (depFetchOwn args)) ++ (depsToFetches dependencies);
 
   cacheInput = oFile: iFile: overrides:
     writeText oFile (toJSON ((listToAttrs (depToFetch iFile))
diff --git a/mknpmcache.js b/mknpmcache.js
index 0f17a26..ba94458 100644
--- a/mknpmcache.js
+++ b/mknpmcache.js
@@ -16,7 +16,7 @@ const lock          = JSON.parse(fs.readFileSync(pkgLockFile, "utf8"))
 const nixPkgs       = JSON.parse(fs.readFileSync(nixPkgsFile, "utf8"))
 
 function traverseDeps(pkg, fn) {
-  Object.entries(pkg.dependencies).forEach(([name, dep]) => {
+    Object.entries(pkg.dependencies).forEach(([name, dep]) => {
     fn(name, dep)
     if (dep.dependencies) traverseDeps(dep, fn)
   })
@@ -29,20 +29,18 @@ async function main(lockfile, nix, cache) {
     return [url, manifest._integrity]
   })
   const hashes = new Map(await Promise.all(promises))
-  traverseDeps(lockfile, (name, dep) => {
+    traverseDeps(lockfile, (name, dep) => {
     if (hashes.has(name)) {
       console.log("overriding package", name)
       dep.integrity = hashes.get(name)
       return
     }
-    if (!dep.integrity || !dep.resolved) {
-      return
-    }
-    if (dep.integrity.startsWith("sha1-")) {
-      assert(hashes.has(dep.resolved))
-      dep.integrity = hashes.get(dep.resolved)
+    let id = dep.resolved || dep.version;
+        if ((dep.from && dep.from.includes("git")) || (dep.integrity && ! dep.integrity.startsWith("sha512-"))) {
+      assert(hashes.has(id))
+      dep.integrity = hashes.get(id)
     } else {
-      assert(dep.integrity == hashes.get(dep.resolved))
+      assert(dep.integrity == hashes.get(id))
     }
   })
   // rewrite lock file to use sha512 hashes from pacote and overrides