diff --git a/types/npm-package-arg/index.d.ts b/types/npm-package-arg/index.d.ts
index bb1a0d8550..fde2710f23 100644
--- a/types/npm-package-arg/index.d.ts
+++ b/types/npm-package-arg/index.d.ts
@@ -20,7 +20,12 @@ declare namespace npa {
      * Something like: 1.2, ^1.7.17, http://x.com/foo.tgz, git+https://github.com/user/foo, bitbucket:user/foo, file:foo.tar.gz or file:../foo/bar/. If not included then the default is latest.
      * @param where Optionally the path to resolve file paths relative to. Defaults to process.cwd()
      */
-    function resolve(name: string, spec: string, where?: string): Result;
+    function resolve(name: string, spec: string, where?: string):
+        FileResult |
+        HostedGitResult |
+        URLResult |
+        AliasResult |
+        RegistryResult;
 
     class Result {
         /**
@@ -33,52 +38,95 @@ declare namespace npa {
          * * directory - A local directory.
          * * remote - An http url (presumably to a tgz)
          */
-        type: "git" | "tag" | "version" | "range" | "file" | "directory" | "remote";
-        /**
-         * If true this specifier refers to a resource hosted on a registry. This is true for tag, version and range types.
-         */
+        type:
+            | "git"
+            | "tag"
+            | "version"
+            | "range"
+            | "file"
+            | "directory"
+            | "remote"
+            | "alias";
+
+        /** If true this specifier refers to a resource hosted on a registry. This is true for tag, version and range types. */
         registry: boolean;
-        /**
-         * If known, the name field expected in the resulting pkg.
-         */
+
+        /** If known, the name field expected in the resulting pkg. */
         name: string | null;
-        /**
-         * If a name is something like @org/module then the scope field will be set to @org. If it doesn't have a scoped name, then scope is null.
-         */
+
+        /** If a name is something like @org/module then the scope field will be set to @org. If it doesn't have a scoped name, then scope is null. */
         scope: string | null;
-        /**
-         * A version of name escaped to match the npm scoped packages specification. Mostly used when making requests against a registry. When name is null, escapedName will also be null.
-         */
+
+        /** A version of name escaped to match the npm scoped packages specification. Mostly used when making requests against a registry. When name is null, escapedName will also be null. */
         escapedName: string | null;
-        /**
-         * The specifier part that was parsed out in calls to npa(arg), or the value of spec in calls to `npa.resolve(name, spec).
-         */
+
+        /** The specifier part that was parsed out in calls to npa(arg), or the value of spec in calls to `npa.resolve(name, spec). */
         rawSpec: string;
-        /**
-         * The normalized specifier, for saving to package.json files. null for registry dependencies.
-         */
+
+        /** The normalized specifier, for saving to package.json files. null for registry dependencies. */
         saveSpec: string | null;
-        /**
-         * The version of the specifier to be used to fetch this resource. null for shortcuts to hosted git dependencies as there isn't just one URL to try with them.
-         */
+
+        /** The version of the specifier to be used to fetch this resource. null for shortcuts to hosted git dependencies as there isn't just one URL to try with them. */
         fetchSpec: string | null;
-        /**
-         * If set, this is a semver specifier to match against git tags with
-         */
+
+        /** If set, this is a semver specifier to match against git tags with */
         gitRange?: string;
-        /**
-         * If set, this is the specific committish to use with a git dependency.
-         */
+
+        /** If set, this is the specific committish to use with a git dependency. */
         gitCommittish?: string;
-        /**
-         * If from === 'hosted' then this will be a hosted-git-info object. This property is not included when serializing the object as JSON.
-         */
-        hosted?: any;
-        /**
-         * The original un-modified string that was provided. If called as npa.resolve(name, spec) then this will be name + '@' + spec.
-         */
+
+        /** If from === 'hosted' then this will be a hosted-git-info object. This property is not included when serializing the object as JSON. */
+        hosted?: HostedGit;
+
+        /** The original un-modified string that was provided. If called as npa.resolve(name, spec) then this will be name + '@' + spec. */
         raw: string;
     }
+
+    interface FileResult extends Result {
+        type: "file" | "directory";
+        where: string;
+        saveSpec: string;
+        fetchSpec: null | string;
+    }
+
+    interface HostedGitResult extends Result {
+        type: "git";
+        hosted: HostedGit;
+        saveSpec: string;
+        fetchSpec: null | string;
+        gitRange: undefined | string;
+        gitCommittish: undefined | string;
+    }
+
+    interface URLResult extends Result {
+        saveSpec: string;
+        type: "git" | "remote";
+        fetchSpec: string;
+        gitCommittish: string | undefined;
+        gitRange: string | undefined;
+    }
+
+    interface AliasResult extends Result {
+        subSpec: Result;
+        registry: true;
+        type: "alias";
+        saveSpec: null;
+        fetchSpec: null;
+    }
+
+    interface RegistryResult extends Result {
+        registry: true;
+        type: "version" | "range" | "tag";
+        saveSpec: null;
+        fetchSpec: string;
+    }
+
+    interface HostedGit {
+        type: string;
+        domain: string;
+        user: string;
+        project: string;
+    }
 }
 
 export = npa;