fix: parse tsconfig as jsonc, resolves #32.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@knighted/duel",
-  "version": "1.0.3",
+  "version": "1.0.4",
   "description": "TypeScript dual packages.",
   "type": "module",
   "main": "dist",
@@ -66,8 +66,8 @@
     "@knighted/specifier": "^1.0.1",
     "find-up": "^6.3.0",
     "glob": "^10.3.3",
-    "read-pkg-up": "^10.0.0",
-    "strip-json-comments": "^5.0.1"
+    "jsonc-parser": "^3.2.0",
+    "read-pkg-up": "^10.0.0"
   },
   "prettier": {
     "arrowParens": "avoid",

src/init.js

@@ -2,9 +2,9 @@ import { cwd } from 'node:process'
 import { parseArgs } from 'node:util'
 import { resolve, join, dirname } from 'node:path'
 import { stat, readFile } from 'node:fs/promises'
-import stripJsonComments from 'strip-json-comments'
 
 import { readPackageUp } from 'read-pkg-up'
+import JSONC from 'jsonc-parser'
 
 import { logError, log } from './util.js'
 
@@ -123,11 +123,16 @@ const init = async args => {
 
     if (stats.isFile()) {
       let tsconfig = null
+      const errors = []
+      const jsonText = (await readFile(configPath)).toString()
 
-      try {
-        tsconfig = JSON.parse(stripJsonComments((await readFile(configPath)).toString()))
-      } catch (err) {
-        logError(`The config file found at ${configPath} is not parsable as JSON.`)
+      tsconfig = JSONC.parse(jsonText, errors, {
+        disallowComments: false,
+        allowTrailingComma: true,
+      })
+
+      if (errors.length) {
+        logError(`The config file found at ${configPath} is not parsable as JSONC.`)
 
         return false
       }

test/__fixtures__/plain/tsconfig.json

@@ -7,7 +7,7 @@
     "declaration": true,
     "strict": false,
     "outDir": "dist",
-    "lib": ["DOM", "ES2015"]
+    "lib": ["DOM", "ES2015"], // dangle comma
   },
   "include": ["src"]
 }

test/integration.js

@@ -70,7 +70,7 @@ describe('duel', () => {
     const spy = t.mock.method(global.console, 'log')
 
     await duel(['-p', 'test/__fixtures__/esmProject/tsconfig.not.json'])
-    assert.ok(spy.mock.calls[0].arguments[1].endsWith('not parsable as JSON.'))
+    assert.ok(spy.mock.calls[0].arguments[1].endsWith('not parsable as JSONC.'))
   })
 
   it('reports errors when using deprecated --target-extension', async t => {