feat: detect package manager from env (#15)

Author: marvinhagemeister

src/pkg_manager.ts

@@ -96,15 +96,26 @@ class Pnpm implements PackageManager {
 
 export type PkgManagerName = "npm" | "yarn" | "pnpm";
 
+function getPkgManagerFromEnv(value: string): PkgManagerName | null {
+  if (value.includes("pnpm/")) return "pnpm";
+  else if (value.includes("yarn/")) return "yarn";
+  else if (value.includes("npm/")) return "npm";
+  else return null;
+}
+
 export async function getPkgManager(
   cwd: string,
   pkgManagerName: PkgManagerName | null
 ) {
-  const { projectDir, pkgManagerName: foundPkgManager } = await findProjectDir(
+  const envPkgManager = process.env.npm_config_user_agent;
+  const fromEnv =
+    envPkgManager !== undefined ? getPkgManagerFromEnv(envPkgManager) : null;
+
+  const { projectDir, pkgManagerName: fromLockfile } = await findProjectDir(
     cwd
   );
 
-  const result = pkgManagerName || foundPkgManager || "npm";
+  const result = pkgManagerName || fromEnv || fromLockfile || "npm";
 
   if (result === "yarn") {
     return new Yarn(projectDir);

src/utils.ts

@@ -141,8 +141,13 @@ export function prettyTime(diff: number) {
   return diff + "ms";
 }
 
-export async function exec(cmd: string, args: string[], cwd: string) {
-  const cp = spawn(cmd, args, { stdio: "inherit", cwd, shell: true });
+export async function exec(
+  cmd: string,
+  args: string[],
+  cwd: string,
+  env?: Record<string, string>
+) {
+  const cp = spawn(cmd, args, { stdio: "inherit", cwd, shell: true, env });
 
   return new Promise<void>((resolve) => {
     cp.on("exit", (code) => {

test/commands.test.ts

@@ -135,6 +135,24 @@ describe("install", () => {
       }
     );
   });
+
+  it("detect pnpm from npm_config_user_agent", async () => {
+    await withTempEnv(
+      ["i", "@std/[email protected]"],
+      async (_, dir) => {
+        assert.ok(
+          await isFile(path.join(dir, "pnpm-lock.yaml")),
+          "pnpm lockfile not created"
+        );
+      },
+      {
+        env: {
+          ...process.env,
+          npm_config_user_agent: `pnpm/8.14.3 ${process.env.npm_config_user_agent}`,
+        },
+      }
+    );
+  });
 });
 
 describe("remove", () => {

test/test_utils.ts

@@ -13,15 +13,23 @@ export interface PkgJson {
   optionalDependencies?: Record<string, string>;
 }
 
-export async function runJsr(args: string[], cwd: string) {
+export async function runJsr(
+  args: string[],
+  cwd: string,
+  env: Record<string, string> = {
+    ...process.env,
+    npm_config_user_agent: "npm/",
+  }
+) {
   const bin = path.join(__dirname, "..", "src", "bin.ts");
   const tsNode = path.join(__dirname, "..", "node_modules", ".bin", "ts-node");
-  return await exec(tsNode, [bin, ...args], cwd);
+  return await exec(tsNode, [bin, ...args], cwd, env);
 }
 
 export async function withTempEnv(
   args: string[],
-  fn: (getPkgJson: () => Promise<PkgJson>, dir: string) => Promise<void>
+  fn: (getPkgJson: () => Promise<PkgJson>, dir: string) => Promise<void>,
+  options: { env?: Record<string, string> } = {}
 ): Promise<void> {
   const dir = await fs.promises.mkdtemp(path.join(os.tmpdir(), "jsr-cli"));
 
@@ -40,7 +48,7 @@ export async function withTempEnv(
   );
 
   try {
-    await runJsr(args, dir);
+    await runJsr(args, dir, options.env);
     const pkgJson = async () =>
       JSON.parse(
         await fs.promises.readFile(path.join(dir, "package.json"), "utf-8")