Add isValidPackcageManager() util

src/utils.test.ts

@@ -4,6 +4,7 @@ import {
 	checkWorkingDirectory,
 	detectPackageManager,
 	getNpxCmd,
+	isValidPackageManager,
 	semverCompare,
 } from "./utils";
 
@@ -70,3 +71,12 @@ describe("detectPackageManager", () => {
 		expect(detectPackageManager("test/fixtures/empty")).toBe(null);
 	});
 });
+
+test("isValidPackageManager", () => {
+	expect(isValidPackageManager("npm")).toBe(true);
+	expect(isValidPackageManager("pnpm")).toBe(true);
+	expect(isValidPackageManager("yarn")).toBe(true);
+
+	expect(isValidPackageManager("")).toBe(false);
+	expect(isValidPackageManager("ppnpm")).toBe(false);
+});

src/utils.ts

@@ -50,3 +50,7 @@ export function detectPackageManager(
 	}
 	return null;
 }
+
+export function isValidPackageManager(name: string): name is PackageManager {
+	return name === "npm" || name === "yarn" || name === "pnpm";
+}