feat: switch to transformWithOxc, drop esbuild direct dependency

CHANGELOG.md

@@ -2,6 +2,16 @@
 
 All notable changes to this project will be documented in this file.
 
+## [1.5.2] - 2026-07-10
+
+### Changed
+
+- **Switch from `transformWithEsbuild` to `transformWithOxc`** — Zero-coverage generation now uses Vite's OXC-based transform (bundled inside Vite via Rolldown) instead of esbuild. OXC is called with `jsx: { runtime: 'automatic' }` to force JSX transformation regardless of the project's `tsconfig.json` (Next.js projects typically set `"jsx": "preserve"` which OXC respects when auto-discovering tsconfig, producing far fewer statements). OXC does not constant-fold `process.env.NODE_ENV` without an explicit `define`, so all branches are preserved. This eliminates the need for `esbuild` as a direct dependency.
+
+### Fixed
+
+- **Remove `esbuild` direct dependency** — No longer needed now that `transformWithOxc` handles TypeScript/TSX compilation. `esbuild` was added in v1.5.1 as a workaround for Vite 8 removing its bundled esbuild; the switch to OXC resolves this cleanly with no extra dependency.
+
 ## [1.5.1] - 2026-07-10
 
 ### Fixed

README.md

@@ -82,8 +82,6 @@ npm install nextcov --save-dev
 npm install @playwright/test --save-dev
 ```
 
-> **Note:** `esbuild` is included as a direct dependency of nextcov (required since Vite 8 no longer bundles it). It will be installed automatically — no manual installation needed.
-
 ## Quick Setup with `nextcov init`
 
 The fastest way to get started is with the `init` command:

package.json

@@ -1,6 +1,6 @@
 {
   "name": "nextcov",
-  "version": "1.5.1",
+  "version": "1.5.2",
   "description": "Collect test coverage for Playwright E2E tests in Next.js applications",
   "author": "Steve Zhang",
   "license": "MIT",
@@ -63,7 +63,6 @@
     "ast-v8-to-istanbul": "^1.0.4",
     "chalk": "^4.1.2",
     "convert-source-map": "^2.0.0",
-    "esbuild": ">=0.21.0",
     "glob": "^11.1.0",
     "istanbul-lib-coverage": "^3.2.0",
     "istanbul-lib-report": "^3.0.1",

src/converter/index.ts

@@ -7,7 +7,7 @@
 
 import { existsSync } from 'node:fs'
 import { resolve, sep } from 'node:path'
-import { parseAstAsync, transformWithEsbuild } from 'vite'
+import { parseAstAsync, transformWithOxc } from 'vite'
 import _astV8ToIstanbul from 'ast-v8-to-istanbul'
 import libCoverage from 'istanbul-lib-coverage'
 import libSourceMaps from 'istanbul-lib-source-maps'
@@ -955,14 +955,14 @@ export class CoverageConverter {
   /**
    * Create empty coverage entry for an uncovered file.
    *
-   * Uses the same esbuild pipeline as Vitest: transformWithEsbuild compiles
-   * TypeScript/TSX → JavaScript with a source map, then parseAstAsync parses
-   * the compiled JS, and astV8ToIstanbul maps positions back to the original
-   * source via the source map.
+   * Uses Vite's OXC transform: transformWithOxc compiles TypeScript/TSX →
+   * JavaScript with a source map, then parseAstAsync parses the compiled JS,
+   * and astV8ToIstanbul maps positions back to the original source via the
+   * source map.
    *
-   * Because the positions come from esbuild (identical to unit/component
-   * coverage), a subsequent `nextcov merge` rebase always finds exact
-   * line:col matches — no fallback, no misattribution.
+   * Because the positions come from OXC (matching Vitest's pipeline),
+   * a subsequent `nextcov merge` rebase always finds exact line:col matches —
+   * no fallback, no misattribution.
    */
   private async createEmptyCoverage(
     filePath: string,
@@ -971,18 +971,19 @@ export class CoverageConverter {
     try {
       const fileUrl = toFileUrl(filePath, this.projectRoot)
 
-      // Transform TypeScript/TSX → JS using esbuild (same as Vitest's pipeline).
+      // Transform TypeScript/TSX → JS using OXC (bundled in Vite via Rolldown).
       // sourcemap:true gives us the position mapping back to the original source.
       //
-      // IMPORTANT: Use platform:'neutral' so esbuild does NOT constant-fold
-      // process.env.NODE_ENV branches. With the default platform ('browser'),
-      // esbuild sees NODE_ENV='production' in the env and eliminates the
-      // 'else' arm of `NODE_ENV === 'production' ? A : B`, producing fewer
-      // branches in the zero-coverage map than Vitest (which uses platform:'browser'
-      // but runs with NODE_ENV='test', so no constant-folding occurs there).
-      const { code: compiledCode, map } = await transformWithEsbuild(code, filePath, {
+      // We explicitly set jsx.runtime:'automatic' to force JSX transformation
+      // regardless of the project's tsconfig.json. Next.js projects typically
+      // have "jsx":"preserve" in tsconfig, which OXC respects when auto-discovering
+      // it — leaving JSX untransformed and producing far fewer statements than
+      // Vitest's pipeline (which overrides the tsconfig via its own OXC config).
+      // OXC does not constant-fold process.env.NODE_ENV without an explicit
+      // define, so all branches are preserved — matching Vitest's behavior.
+      const { code: compiledCode, map } = await transformWithOxc(code, filePath, {
         sourcemap: true,
-        platform: 'neutral',
+        jsx: { runtime: 'automatic' },
       })
 
       // Parse the compiled JS with Vite's fast Rollup-based parser