feat: code splitting rework /w preserveModules support

.eslintrc.js

@@ -22,6 +22,7 @@ module.exports = {
     "prefer-template": "error",
     "sort-vars": "error",
     "unicorn/no-fn-reference-in-iterator": "off",
+    "unicorn/no-null": "off",
     "unicorn/no-reduce": "off",
     "unicorn/prefer-set-has": "off",
     "unicorn/prevent-abbreviations": "off",

__tests__/helpers/index.ts

@@ -1,7 +1,7 @@
 /* eslint-disable jest/no-export */
 import path from "path";
 import fs from "fs-extra";
-import { Plugin, rollup, OutputOptions } from "rollup";
+import { Plugin, rollup, InputOptions, OutputOptions } from "rollup";
 
 import styles from "../../src";
 import { Options } from "../../src/types";
@@ -13,6 +13,7 @@ export type WriteData = {
   outDir?: string;
   options?: Options;
   plugins?: Plugin[];
+  inputOpts?: InputOptions;
   outputOpts?: OutputOptions;
 };
 
@@ -40,12 +41,11 @@ export const fixture = (...args: string[]): string =>
 export async function write(data: WriteData): Promise<WriteResult> {
   const outDir = fixture("dist", data.outDir ?? data.title ?? "");
   const input = Array.isArray(data.input) ? data.input.map(i => fixture(i)) : fixture(data.input);
-  const multiEntry = Array.isArray(data.input) ? data.input.length > 1 : false;
 
   const bundle = await rollup({
+    ...data.inputOpts,
     input,
     plugins: data.plugins ?? [styles(data.options)],
-    preserveModules: multiEntry,
     onwarn: (warning, warn) => {
       if (warning.code === "EMPTY_BUNDLE") return;
       if (warning.source === "lit-element") return;

__tests__/index.test.ts

@@ -348,6 +348,26 @@ validateMany("code-splitting", [
       sourceMap: true,
     },
   },
+  {
+    title: "preserve-modules",
+    input: "code-splitting/index.js",
+    options: {
+      mode: "extract",
+      modules: true,
+      sourceMap: true,
+    },
+    inputOpts: { preserveModules: true },
+  },
+  {
+    title: "preserve-modules-single",
+    input: "code-splitting/index.js",
+    options: {
+      mode: "extract",
+      modules: true,
+      sourceMap: true,
+    },
+    inputOpts: { preserveModules: true },
+  },
   {
     title: "multi-entry",
     input: ["code-splitting/index.js", "code-splitting/index2.js"],

package.json

@@ -94,7 +94,7 @@
     "eslint-config-prettier": "^6.11.0",
     "eslint-import-resolver-node": "^0.3.3",
     "eslint-plugin-import": "^2.20.2",
-    "eslint-plugin-jest": "^23.11.0",
+    "eslint-plugin-jest": "^23.13.0",
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-unicorn": "^20.0.0",
     "fibers": "^5.0.0",
@@ -109,7 +109,7 @@
     "postcss-custom-properties": "^9.1.1",
     "prettier": "^2.0.5",
     "rollup": "^2.10.2",
-    "rollup-plugin-dts": "^1.4.3",
+    "rollup-plugin-dts": "^1.4.4",
     "rollup-plugin-lit-css": "^2.0.3",
     "rollup-plugin-node-externals": "^2.1.6",
     "rollup-plugin-terser": "^5.3.0",

src/.eslintrc.js

@@ -48,6 +48,7 @@ module.exports = {
     "prefer-template": "error",
     "sort-vars": "error",
     "unicorn/no-fn-reference-in-iterator": "off",
+    "unicorn/no-null": "off",
     "unicorn/no-reduce": "off",
     "unicorn/prefer-set-has": "off",
     "unicorn/prevent-abbreviations": "off",