feat: add definitely-typed module

Author: velut

lib/utils/definitely-typed.test.ts

@@ -0,0 +1,14 @@
+import { expect, test } from "vitest";
+import { getDTPackageName, isDTPackage } from "./definitely-typed";
+
+test("getDTPackageName", () => {
+	expect(getDTPackageName("foo")).toBe("@types/foo");
+	expect(getDTPackageName("@foo/bar")).toBe("@types/foo__bar");
+	expect(getDTPackageName("@types/foo")).toBe("@types/foo");
+});
+
+test("isDTPackage", () => {
+	expect(isDTPackage("foo")).toBeFalsy();
+	expect(isDTPackage("@foo/bar")).toBeFalsy();
+	expect(isDTPackage("@types/foo")).toBeTruthy();
+});

lib/utils/definitely-typed.ts

@@ -0,0 +1,13 @@
+/**
+`getDTPackageName` returns the name of the corresponding DefinitelyTyped package
+(e.g., `foo` => `@types/foo`, `@foo/bar` => `@types/foo__bar`).
+*/
+export function getDTPackageName(name: string): string {
+	if (name.startsWith("@types/")) return name;
+	return `@types/${name.replace("@", "").replace("/", "__")}`;
+}
+
+/** `isDTPackage` returns true if the package belongs to the `@types` scope. */
+export function isDTPackage(name: string): boolean {
+	return name.startsWith("@types/");
+}