feat(create): detect package managers and run install

Made-with: Cursor

packages/create/src/install.ts

@@ -0,0 +1,22 @@
+import { spawnSync } from "node:child_process";
+import type { PackageManagerName } from "./package-manager.js";
+import { spawnInstall } from "./package-manager.js";
+import { CliError } from "./errors.js";
+
+export function installDependencies(
+  cwd: string,
+  manager: PackageManagerName
+): void {
+  const { cmd, args } = spawnInstall(manager);
+  const res = spawnSync(cmd, args, {
+    cwd,
+    stdio: "inherit",
+    env: { ...process.env, CI: "1" },
+  });
+  if (res.error || res.status !== 0) {
+    throw new CliError(
+      `${cmd} ${args.join(" ")} failed in ${cwd}`,
+      "INSTALL_FAILED"
+    );
+  }
+}

packages/create/src/package-manager.ts

@@ -0,0 +1,35 @@
+import { spawnSync } from "node:child_process";
+
+export type PackageManagerName = "npm" | "pnpm" | "yarn" | "bun";
+
+const ORDER: PackageManagerName[] = ["pnpm", "npm", "yarn", "bun"];
+
+export function isManagerAvailable(name: PackageManagerName): boolean {
+  const result = spawnSync(name, ["--version"], { stdio: "ignore" });
+  return result.status === 0;
+}
+
+export function detectAvailableManagers(): PackageManagerName[] {
+  return ORDER.filter(isManagerAvailable);
+}
+
+/** Install argv; cwd is applied by install.ts via spawnSync `cwd` option. */
+export function spawnInstall(name: PackageManagerName): {
+  cmd: string;
+  args: string[];
+} {
+  switch (name) {
+    case "pnpm":
+      return { cmd: "pnpm", args: ["install"] };
+    case "npm":
+      return { cmd: "npm", args: ["install"] };
+    case "yarn":
+      return { cmd: "yarn", args: ["install"] };
+    case "bun":
+      return { cmd: "bun", args: ["install"] };
+    default: {
+      const _: never = name;
+      throw new Error(`unsupported manager ${_}`);
+    }
+  }
+}