feat(rollup): allow regular expressions in externals array

src/builder/rollup.ts

@@ -15,7 +15,7 @@ import dts from "rollup-plugin-dts";
 import replace from "@rollup/plugin-replace";
 import { resolve, dirname, normalize, extname, isAbsolute } from "pathe";
 import { resolvePath, resolveModuleExportNames } from "mlly";
-import { getpkg, tryResolve, warn } from "../utils";
+import { arrayIncludes, getpkg, tryResolve, warn } from "../utils";
 import type { BuildContext } from "../types";
 import { esbuild } from "./plugins/esbuild";
 import { JSONPlugin } from "./plugins/json";
@@ -227,7 +227,7 @@ export function getRollupOptions(ctx: BuildContext): RollupOptions {
 
     external(id) {
       const pkg = getpkg(id);
-      const isExplicitExternal = ctx.options.externals.includes(pkg);
+      const isExplicitExternal = arrayIncludes(ctx.options.externals, pkg);
       if (isExplicitExternal) {
         return true;
       }

src/types.ts

@@ -66,7 +66,7 @@ export interface BuildOptions {
   declaration?: boolean;
   outDir: string;
   stub: boolean;
-  externals: string[];
+  externals: (string|RegExp)[];
   dependencies: string[];
   peerDependencies: string[];
   devDependencies: string[];

src/utils.ts

@@ -162,3 +162,7 @@ export function extractExportFilenames(
       )
   );
 }
+
+export function arrayIncludes (arr: (string|RegExp)[], searchElement: string) {
+  return arr.some(entry => entry instanceof RegExp ? entry.test(searchElement) : entry === searchElement);
+}

src/validate.ts

@@ -2,7 +2,7 @@ import { existsSync } from "node:fs";
 import chalk from "chalk";
 import { resolve } from "pathe";
 import { PackageJson } from "pkg-types";
-import { extractExportFilenames, getpkg, warn } from "./utils";
+import { arrayIncludes, extractExportFilenames, getpkg, warn } from "./utils";
 import { BuildContext } from "./types";
 
 export function validateDependencies(ctx: BuildContext) {
@@ -22,7 +22,7 @@ export function validateDependencies(ctx: BuildContext) {
   }
   for (const id of usedDependencies) {
     if (
-      !ctx.options.externals.includes(id) &&
+      !arrayIncludes(ctx.options.externals, id) &&
       !id.startsWith("chunks/") &&
       !ctx.options.dependencies.includes(getpkg(id)) &&
       !ctx.options.peerDependencies.includes(getpkg(id))

test/utils.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect } from "vitest";
-import { extractExportFilenames, inferExportType } from "../src/utils";
+import { arrayIncludes, extractExportFilenames, inferExportType } from "../src/utils";
 
 describe("inferExportType", () => {
   it("infers export type by condition", () => {
@@ -38,3 +38,14 @@ describe("extractExportFilenames", () => {
     ]);
   });
 });
+
+describe("arrayIncludes", () => {
+  it("handles strings", () => {
+    expect(arrayIncludes(["test1", "test2"], "test1")).to.eq(true);
+    expect(arrayIncludes(["test1", "test2"], "test3")).to.eq(false);
+  });
+  it("handles regular expressions", () => {
+    expect(arrayIncludes([/t1$/, "test2"], "test1")).to.eq(true);
+    expect(arrayIncludes([/t3$/, "test2"], "test1")).to.eq(false);
+  });
+});