fix: improve package manager detection logic

Author: marvinhagemeister

src/bin.ts

@@ -3,9 +3,8 @@ import * as kl from "kolorist";
 import * as fs from "node:fs";
 import * as path from "node:path";
 import { parseArgs } from "node:util";
-import { install, remove, setupNpmRc } from "./commands";
-import { JsrPackage, findLockFile, setDebug } from "./utils";
-import { detectPackageManager } from "./pkg_manager";
+import { install, remove } from "./commands";
+import { JsrPackage, setDebug } from "./utils";
 
 const args = process.argv.slice(2);
 

src/commands.ts

@@ -1,7 +1,7 @@
 import * as path from "node:path";
 import * as fs from "node:fs";
-import { JsrPackage, findLockFile } from "./utils";
-import { detectPackageManager } from "./pkg_manager";
+import { JsrPackage } from "./utils";
+import { detectPackageManager, getProjectDir } from "./pkg_manager";
 
 const JSR_NPMRC = `@jsr:registry=https://npm.jsr.io\n`;
 
@@ -27,16 +27,15 @@ export interface InstallOptions {
 }
 
 export async function install(packages: JsrPackage[], options: InstallOptions) {
-  const lockFilePath = await findLockFile(process.cwd());
-  const projectDir = path.dirname(lockFilePath);
+  const { projectDir, lockFilePath } = await getProjectDir(process.cwd());
   await setupNpmRc(projectDir);
 
-  const pkgManager = await detectPackageManager(lockFilePath);
+  const pkgManager = await detectPackageManager(lockFilePath, projectDir);
   await pkgManager.install(packages, options);
 }
 
 export async function remove(packages: JsrPackage[]) {
-  const lockFilePath = await findLockFile(process.cwd());
-  const pkgManager = await detectPackageManager(lockFilePath);
+  const { projectDir, lockFilePath } = await getProjectDir(process.cwd());
+  const pkgManager = await detectPackageManager(lockFilePath, projectDir);
   await pkgManager.remove(packages);
 }

src/pkg_manager.ts

@@ -1,7 +1,7 @@
 import { promisify } from "node:util";
 import * as path from "node:path";
 import { InstallOptions } from "./commands";
-import { JsrPackage, logDebug } from "./utils";
+import { JsrPackage, findLockFile, findPackageJson, logDebug } from "./utils";
 import * as cp from "node:child_process";
 
 const execAsync = promisify(cp.exec);
@@ -84,17 +84,40 @@ class Pnpm implements PackageManager {
   }
 }
 
-export function detectPackageManager(lockfilePath: string): PackageManager {
-  const filename = path.basename(lockfilePath);
-  const cwd = path.dirname(lockfilePath);
+export async function getProjectDir(cwd: string): Promise<{
+  projectDir: string;
+  lockFilePath: string | null;
+}> {
+  const lockFilePath = await findLockFile(cwd);
+  if (lockFilePath !== null) {
+    const projectDir = path.dirname(lockFilePath);
+    return { lockFilePath, projectDir };
+  }
+
+  const pkgJsonPath = await findPackageJson(cwd);
+  if (pkgJsonPath !== null) {
+    const projectDir = path.dirname(pkgJsonPath);
+    return { lockFilePath: null, projectDir };
+  }
+
+  return { lockFilePath: null, projectDir: cwd };
+}
 
-  if (filename === "package-lock.json") {
-    return new Npm(cwd);
-  } else if (filename === "yarn.lock") {
-    return new Yarn(cwd);
-  } else if (filename === "pnpm-lock.yml") {
-    return new Pnpm(cwd);
+export function detectPackageManager(
+  lockFilePath: string | null,
+  projectDir: string
+): PackageManager {
+  if (lockFilePath !== null) {
+    const filename = path.basename(lockFilePath);
+    if (filename === "package-lock.json") {
+      return new Npm(projectDir);
+    } else if (filename === "yarn.lock") {
+      return new Yarn(projectDir);
+    } else if (filename === "pnpm-lock.yml") {
+      return new Pnpm(projectDir);
+    }
   }
 
-  throw new Error("Could not determine package manager");
+  // Fall back to npm if no lockfile is present.
+  return new Npm(projectDir);
 }

src/utils.ts

@@ -53,7 +53,23 @@ async function fileExists(file: string): Promise<boolean> {
   }
 }
 
-export async function findLockFile(dir: string): Promise<string> {
+export async function findPackageJson(dir: string): Promise<string | null> {
+  const file = path.join(dir, "package.json");
+
+  if (await fileExists(file)) {
+    return file;
+  }
+
+  const prev = dir;
+  dir = path.dirname(dir);
+  if (dir === prev) {
+    return null;
+  }
+
+  return findPackageJson(dir);
+}
+
+export async function findLockFile(dir: string): Promise<string | null> {
   const npmLockfile = path.join(dir, "package-lock.json");
   if (await fileExists(npmLockfile)) {
     logDebug("Using npm package manager");
@@ -75,7 +91,7 @@ export async function findLockFile(dir: string): Promise<string> {
   const prev = dir;
   dir = path.dirname(dir);
   if (dir === prev) {
-    throw new Error(`Could not find lockfile.`);
+    return null;
   }
 
   return findLockFile(dir);