Try this combination of ESM and CJS to see if it works

Author: leeyi45

lib/vitest-reporter/build/coverage-reporter.js renamed to lib/vitest-reporter/build/coverage-reporter.cjs

@@ -1,6 +1,8 @@
-// src/coverage-reporter.ts
-import fs from "fs";
-import { ReportBase } from "istanbul-lib-report";
+"use strict";
+
+// src/coverage-reporter.cts
+var fs = require("fs");
+var report = require("istanbul-lib-report");
 function isFull(metrics) {
   return metrics.statements.pct === 100 && metrics.branches.pct === 100 && metrics.functions.pct === 100 && metrics.lines.pct === 100;
 }
@@ -37,12 +39,12 @@ function getUncoveredLines(node) {
   return ranges;
 }
 var headers = ["Statements", "Branches", "Functions", "Lines"];
-var GithubActionsCoverageReporter = class extends ReportBase {
+module.exports = class GithubActionsCoverageReporter extends report.ReportBase {
   skipEmpty;
   skipFull;
   results = {};
   cw = null;
-  watermarks = null;
+  watermarks = {};
   constructor(opts) {
     super(opts);
     this.skipEmpty = Boolean(opts.skipEmpty);
@@ -84,7 +86,7 @@ var GithubActionsCoverageReporter = class extends ReportBase {
     return this.onSummary(node);
   }
   formatter(pct, watermark) {
-    if (!this.watermarks || this.watermarks[watermark] === void 0) return `<td>${pct}%</td>`;
+    if (this.watermarks[watermark] === void 0) return `<td>${pct}%</td>`;
     const [low, high] = this.watermarks[watermark];
     if (pct < low) {
       return `<td><p style="color:red">${pct}%</p></td>`;
@@ -123,6 +125,3 @@ var GithubActionsCoverageReporter = class extends ReportBase {
     this.cw.close();
   }
 };
-export {
-  GithubActionsCoverageReporter as default
-};

lib/vitest-reporter/package.json

@@ -19,7 +19,7 @@
   },
   "scripts": {
     "build": "yarn build:coverage-reporter && yarn build:test-reporter",
-    "build:coverage-reporter": "esbuild --outfile=./build/coverage-reporter.js --format=esm --bundle=true --minify=false --external:\"istanbul-lib-report\" --platform=node src/coverage-reporter.ts",
+    "build:coverage-reporter": "esbuild --outfile=./build/coverage-reporter.cjs --format=cjs --bundle=true --minify=false --external:\"istanbul-lib-report\" --platform=node src/coverage-reporter.cts",
     "build:test-reporter": "esbuild --outfile=./build/test-reporter.js --format=esm --bundle=true  --minify --external:\"vitest*\" --platform=node src/test-reporter.ts",
     "test": "vitest"
   }

lib/vitest-reporter/src/__tests__/coverage.test.ts

@@ -1,14 +1,14 @@
 import fs from 'fs';
 import { describe, expect, it as baseIt, vi } from 'vitest';
-import CoverageReporter from '../coverage-reporter.js';
+import CoverageReporter from '../coverage-reporter.cjs'
 
 vi.spyOn(fs, 'createWriteStream').mockReturnValue({
   write: () => true,
   close: () => {}
 } as any);
 
 describe(CoverageReporter, () => {
-  const it = baseIt.extend<{ reporter: CoverageReporter }>({
+  const it = baseIt.extend<{ reporter: typeof CoverageReporter }>({
     reporter: new CoverageReporter({})
   });
 

lib/vitest-reporter/src/__tests__/test-reporter.test.ts

@@ -3,7 +3,7 @@ import { describe, expect, it as baseIt, vi } from 'vitest';
 import TestReporter from '../test-reporter.js';
 
 vi.spyOn(fs, 'createWriteStream').mockImplementation(() => ({
-  write: () => {},
+  write: () => true,
   close: () => {}
 } as any));
 

lib/vitest-reporter/src/coverage-reporter.ts renamed to lib/vitest-reporter/src/coverage-reporter.cts

@@ -1,12 +1,13 @@
 /**
- * For whatever reason, this reporter doesn't really work if its compiled to ESM
- * so its compiled to CJS
+ * For whatever reason, this reporter doesn't really work if its written in ESM
+ * so its written in and compiled to CJS
  *
  * Heavily based on the default text reporter
  */
-import fs from 'fs';
+
+import fs = require('fs')
+import report = require('istanbul-lib-report');
 import type { CoverageSummary } from 'istanbul-lib-coverage';
-import { ReportBase, type ContextOptions, type ReportNode, type Watermarks } from 'istanbul-lib-report';
 
 /**
  * Determines if the coverage summary has full coverage
@@ -23,7 +24,7 @@ function isFull(metrics: CoverageSummary) {
 /**
  * Determines the uncovered lines
  */
-function getUncoveredLines(node: ReportNode) {
+function getUncoveredLines(node: report.ReportNode) {
   if (node.isSummary()) {
     return [];
   }
@@ -77,12 +78,12 @@ interface ResultObject {
 /**
  * A Vitest coverage reporter that writes to the Github Actions summary
  */
-export default class GithubActionsCoverageReporter extends ReportBase {
+module.exports = class GithubActionsCoverageReporter extends report.ReportBase {
   private readonly skipEmpty: boolean;
   private readonly skipFull: boolean;
   private readonly results: Record<string, ResultObject> = {};
   private cw: fs.WriteStream | null = null;
-  private watermarks: Partial<Watermarks> | null = null;
+  private watermarks: Partial<report.Watermarks> = {};
 
   constructor(opts: any) {
     super(opts);
@@ -91,7 +92,7 @@ export default class GithubActionsCoverageReporter extends ReportBase {
     this.skipFull = Boolean(opts.skipFull);
   }
 
-  onStart(_node: any, context: ContextOptions) {
+  onStart(_node: any, context: report.ContextOptions) {
     if (!process.env.GITHUB_STEP_SUMMARY) {
       console.log('Reporter not being executed in Github Actions environment');
       return;
@@ -108,7 +109,7 @@ export default class GithubActionsCoverageReporter extends ReportBase {
     this.cw.write('</tr></thead><tbody>');
   }
 
-  onSummary(node: ReportNode) {
+  onSummary(node: report.ReportNode) {
     const nodeName = node.getRelativeName() || 'All Files';
     const rawMetrics = node.getCoverageSummary(false);
     const isEmpty = rawMetrics.isEmpty();
@@ -129,12 +130,12 @@ export default class GithubActionsCoverageReporter extends ReportBase {
     };
   }
 
-  onDetail(node: ReportNode) {
+  onDetail(node: report.ReportNode) {
     return this.onSummary(node);
   }
 
-  private formatter(pct: number, watermark: keyof Watermarks) {
-    if (!this.watermarks || this.watermarks[watermark] === undefined) return `<td>${pct}%</td>`;
+  private formatter(pct: number, watermark: keyof report.Watermarks) {
+    if (this.watermarks[watermark] === undefined) return `<td>${pct}%</td>`;
     const [low, high] = this.watermarks[watermark];
 
     if (pct < low) {

lib/vitest-reporter/tsconfig.json

@@ -1,7 +1,7 @@
 // Repotools regular tsconfig
 {
   "extends": ["../tsconfig.json"],
-  "include": ["src"],
+  "include": ["src/coverage-reporter.cts", "src/**/*.ts"],
   "compilerOptions": {
     "module": "nodenext",
     "moduleResolution": "nodenext",

lib/vitest-reporter/vitest.config.js

@@ -4,6 +4,9 @@ import { defineConfig } from 'vitest/config';
 import rootConfig from '../../vitest.config.js';
 
 export default defineConfig({
+  esbuild: {
+    include: ['**/*.{cts,ts}']
+  },
   optimizeDeps: {
     include: ['istanbul-lib-report'],
   },