feat: added support for adding additional rollup plugins

packages/packem/__tests__/helpers.ts

@@ -51,7 +51,7 @@ export const installPackage = async (fixturePath: string, packageName: string):
 
 export const createPackemConfig = async (
     fixturePath: string,
-    config: BuildConfig | BuildConfig[] = {},
+    config: BuildConfig | string = {},
     transformer: "esbuild" | "swc" | "sucrase" = "esbuild",
     isolatedDeclarationTransformer: "swc" | "typescript" | "oxc" | undefined = undefined,
 ): Promise<void> => {
@@ -68,7 +68,7 @@ ${isolatedDeclarationTransformer ? `import isolatedDeclarationTransformer from "
 export default defineConfig({
     transformer,
     ${isolatedDeclarationTransformer ? `isolatedDeclarationTransformer,` : ""}
-    ${JSON.stringify(config, null, 4).slice(1, -1)}
+    ${typeof config === "string" ? config : JSON.stringify(config, null, 4).slice(1, -1)}
 });
 `,
         {

packages/packem/__tests__/intigration/packem.test.ts

@@ -0,0 +1,71 @@
+import { rm } from "node:fs/promises";
+
+import { readFileSync, writeFileSync } from "@visulima/fs";
+import type { Plugin } from "rollup";
+import { temporaryDirectory } from "tempy";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+
+import { createPackageJson, createPackemConfig, createTsConfig, execPackemSync, installPackage } from "../helpers";
+
+describe("packem build --jit", () => {
+    let temporaryDirectoryPath: string;
+
+    beforeEach(async () => {
+        temporaryDirectoryPath = temporaryDirectory();
+    });
+
+    afterEach(async () => {
+        await rm(temporaryDirectoryPath, { recursive: true });
+    });
+
+    it("should append plugins before and after a named plugin", async () => {
+        expect.assertions(4);
+
+        await installPackage(temporaryDirectoryPath, "typescript");
+
+        writeFileSync(`${temporaryDirectoryPath}/src/index.ts`, `export default () => 'index';`);
+
+        createTsConfig(temporaryDirectoryPath, {});
+        createPackageJson(temporaryDirectoryPath, {
+            devDependencies: {
+                typescript: "*",
+            },
+            main: "./dist/index.cjs",
+        });
+        await createPackemConfig(
+            temporaryDirectoryPath,
+            `rollup: {
+        plugins: [
+            {
+                before: "packem:esbuild",
+                plugin: <Plugin>{
+                    load() {
+                        console.log("packem:test-plugin:before");
+                    },
+                    name: "packem:test-plugin:before"
+                }
+            },
+            {
+                after: "packem:esbuild",
+                plugin: <Plugin>{
+                    load() {
+                        console.log("packem:test-plugin:after");
+                    },
+                    name: "packem:test-plugin:after"
+                }
+            }
+        ]
+}`,
+        );
+
+        const binProcess = await execPackemSync("build", [], {
+            cwd: temporaryDirectoryPath,
+        });
+
+        expect(binProcess.stderr).toBe("");
+        expect(binProcess.exitCode).toBe(0);
+
+        expect(binProcess.stdout).toContain("packem:test-plugin:before");
+        expect(binProcess.stdout).toContain("packem:test-plugin:after");
+    });
+});