feat: resolve full dependency tree

src/domain/getPackageDependencies.ts

@@ -6,6 +6,7 @@ import {
   PackageVersion,
 } from "./types";
 import { maxSatisfying } from "semver";
+import axios from "axios";
 
 /**
  * A function which resolves the direct dependencies of a
@@ -25,7 +26,7 @@ export async function getPackageDependencies(
   packageName: PackageName,
   packageVersion: PackageVersion,
   getPackage: PackageGetter,
-): Promise<Record<PackageName, PackageVersion>> {
+): Promise<Record<PackageName, Package>> {
   const npmPackage: NPMPackage = await getPackage(packageName);
 
   const packageForVersion = npmPackage.versions[packageVersion];
@@ -34,15 +35,48 @@ export async function getPackageDependencies(
   }
 
   const dependenciesWithRange = packageForVersion?.dependencies ?? {};
-  const dependencies: Record<PackageName, PackageVersion> = {};
+  const dependencies: Record<string, Package> = {};
 
   for (const [dependencyName, range] of Object.entries(dependenciesWithRange)) {
-    const dependency: NPMPackage = await getPackage(dependencyName);
-
-    const maxSatisfyingVersion =
-      maxSatisfying(Object.keys(dependency.versions), range) ?? range;
-    dependencies[dependencyName] = maxSatisfyingVersion;
+    dependencies[dependencyName] = await resolveDependenciesRecursively(
+      dependencyName,
+      range,
+    );
   }
 
   return dependencies;
 }
+
+async function resolveDependenciesRecursively(
+  name: string,
+  range: string,
+): Promise<Package> {
+  const npmPackage = await (
+    await axios.get(`https://registry.npmjs.org/${name}`)
+  ).data;
+
+  const maxSatisfyingVersion = maxSatisfying(
+    Object.keys(npmPackage.versions),
+    range,
+  ) as string;
+
+  if (!npmPackage.versions[maxSatisfyingVersion]) {
+    throw new Error();
+  }
+
+  const dependencies: Record<string, Package> = {};
+  for (const [name, range] of Object.entries(
+    npmPackage.versions[maxSatisfyingVersion].dependencies ?? {},
+  )) {
+    // eslint-disable-next-line
+    // @ts-ignore
+    dependencies[name] = await resolveDependenciesRecursively(name, range);
+  }
+
+  return { version: maxSatisfyingVersion, dependencies };
+}
+
+interface Package {
+  version: string;
+  dependencies: Record<PackageName, Package>;
+}

tests/routes/getPackage.integration.test.ts

@@ -33,7 +33,7 @@ describe("/package/:packageName/:packageVersion endpoint", () => {
     server.close();
   });
 
-  it("responds with list of dependencies", async () => {
+  it("responds with a tree of dependencies", async () => {
     const packageName = "react";
     const version = "16.3.0";
     const address = `http://localhost:${port}/package/${packageName}/${version}`;
@@ -42,7 +42,12 @@ describe("/package/:packageName/:packageVersion endpoint", () => {
     const expectedResponse = {
       name: "react",
       version: "16.3.0",
-      dependencies: { "loose-envify": "1.1.0" },
+      dependencies: {
+        "loose-envify": {
+          version: "1.1.0",
+          dependencies: { "js-tokens": { version: "1.0.3", dependencies: {} } },
+        },
+      },
     };
 
     expect(response.data).toEqual(expectedResponse);