Fix require() of the CommonJS build

The package is "type": "module", so Node treated dist/feascript.cjs.js
as an ES module and require("feascript") failed with ERR_REQUIRE_ESM.
Build the CommonJS bundle as dist/feascript.cjs and point "main" and
"exports.require" at it. import is unchanged.

Author: nikoscham

dist/feascript.cjs.js dist/feascript.cjsdist/feascript.cjs.js renamed to dist/feascript.cjs

@@ -2,12 +2,12 @@
   "name": "feascript",
   "version": "0.3.0",
   "description": "Finite element simulation library built in JavaScript",
-  "main": "dist/feascript.cjs.js",
+  "main": "dist/feascript.cjs",
   "module": "dist/feascript.esm.js",
   "browser": "dist/feascript.umd.js",
   "exports": {
     "import": "./dist/feascript.esm.js",
-    "require": "./dist/feascript.cjs.js"
+    "require": "./dist/feascript.cjs"
   },
   "files": [
     "dist",

dist/feascript.cjs.js.map

@@ -13,7 +13,7 @@ const rewriteWorkerUrl = {
   renderChunk(code, chunk) {
     // Replace the source-relative wrapper.js path with the dist-sibling path so the
     // bundle resolves feascript-worker.esm.js correctly from any host path.
-    if (/feascript\.(esm|cjs|umd)\.js$/.test(chunk.fileName)) {
+    if (/feascript\.(esm\.js|cjs|umd\.js)$/.test(chunk.fileName)) {
       return {
         code: code.replace('"./wrapper.js"', '"./feascript-worker.esm.js"'),
         map: null,
@@ -46,7 +46,7 @@ export default [
     input: "src/index.js",
     output: [
       {
-        file: "dist/feascript.cjs.js",
+        file: "dist/feascript.cjs", // .cjs, since the package is "type": "module"
         format: "cjs",
         sourcemap: true,
       },