Add support for debugging Next.js core (#13101)

Note this is only for the Next.js core, will look at a configuration for the debugger for Next.js apps soon.

.vscode/launch.json

@@ -0,0 +1,43 @@
+{
+  // Use IntelliSense to learn about possible attributes.
+  // Hover to view descriptions of existing attributes.
+  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Launch app development",
+      "type": "node",
+      "request": "launch",
+      "cwd": "${workspaceFolder}",
+      "runtimeExecutable": "yarn",
+      "runtimeArgs": ["run", "debug", "dev", "test/integration/basic"],
+      "port": 9229
+    },
+    {
+      "name": "Launch app build",
+      "type": "node",
+      "request": "launch",
+      "cwd": "${workspaceFolder}",
+      "runtimeExecutable": "yarn",
+      "runtimeArgs": ["run", "debug", "build", "test/integration/basic"],
+      "port": 9229
+    },
+    {
+      "name": "Launch app production",
+      "type": "node",
+      "request": "launch",
+      "cwd": "${workspaceFolder}",
+      "runtimeExecutable": "yarn",
+      "runtimeArgs": ["run", "debug", "start", "test/integration/basic"],
+      "port": 9229
+    },
+    {
+      "type": "node",
+      "request": "attach",
+      "name": "Attach to existing debugger",
+      "port": 9229,
+      "skipFiles": ["<node_internals>/**"],
+      "outFiles": ["${workspaceFolder}/packages/next/dist/**/*"]
+    }
+  ]
+}

package.json

@@ -31,7 +31,8 @@
     "publish-canary": "lerna version prerelease --preid canary --force-publish && release --pre",
     "publish-stable": "lerna version --force-publish",
     "lint-staged": "lint-staged",
-    "next": "node packages/next/dist/bin/next"
+    "next": "node packages/next/dist/bin/next",
+    "debug": "node --inspect-brk packages/next/dist/bin/next"
   },
   "pre-commit": "lint-staged",
   "devDependencies": {

packages/next/taskfile-babel.js

@@ -1,7 +1,7 @@
 // taskr babel plugin with Babel 7 support
 // https://github.com/lukeed/taskr/pull/305
 
-const extname = require('path').extname
+const path = require('path')
 const transform = require('@babel/core').transform
 
 const babelClientOpts = {
@@ -88,6 +88,10 @@ module.exports = function (task) {
     const babelOpts =
       serverOrClient === 'client' ? babelClientOpts : babelServerOpts
 
+    const filePath = path.join(file.dir, file.base)
+    const fullFilePath = path.join(__dirname, filePath)
+    const distFilePath = path.dirname(path.join(__dirname, 'dist', filePath))
+
     const options = {
       ...babelOpts,
       plugins: [
@@ -108,11 +112,14 @@ module.exports = function (task) {
       compact: true,
       babelrc: false,
       configFile: false,
-      filename: file.base,
+      cwd: __dirname,
+      filename: path.join(file.dir, file.base),
+      sourceFileName: path.relative(distFilePath, fullFilePath),
       sourceMaps: true,
     }
+
     const output = transform(file.data, options)
-    const ext = extname(file.base)
+    const ext = path.extname(file.base)
 
     // Replace `.ts|.tsx` with `.js` in files with an extension
     if (ext) {
@@ -132,6 +139,8 @@ module.exports = function (task) {
     if (output.map) {
       const map = `${file.base}.map`
 
+      output.code += Buffer.from(`\n//# sourceMappingURL=${map}`)
+
       // add sourcemap to `files` array
       this._.files.push({
         base: map,