feat: .jsonc config support (#132)

README.md

@@ -9,10 +9,11 @@ c12 (pronounced as /siːtwelv/, like c-twelve) is a smart configuration loader.
 
 ## Features
 
-- JSON, CJS, Typescript, and ESM config loader with [unjs/jiti](https://github.com/unjs/jiti)
-- RC config support with [unjs/rc9](https://github.com/unjs/rc9)
-- Multiple sources merged with [unjs/defu](https://github.com/unjs/defu)
+- `.json`, `.js`, `.ts`, and `.mjs` config loader with [unjs/jiti](https://github.com/unjs/jiti)
+- `.jsonc` config support with [jsonc-parser](https://github.com/microsoft/node-jsonc-parser)
+- `.rc` config support with [unjs/rc9](https://github.com/unjs/rc9)
 - `.env` support with [dotenv](https://www.npmjs.com/package/dotenv)
+- Multiple sources merged with [unjs/defu](https://github.com/unjs/defu)
 - Reads config from the nearest `package.json` file
 - [Extends configurations](https://github.com/unjs/c12#extending-configuration) from multiple local or git sources
 - Overwrite with [environment-specific configuration](#environment-specific-configuration)

package.json

@@ -35,6 +35,7 @@
     "dotenv": "^16.3.2",
     "giget": "^1.2.1",
     "jiti": "^1.21.0",
+    "jsonc-parser": "^3.2.1",
     "mlly": "^1.5.0",
     "ohash": "^1.1.3",
     "pathe": "^1.1.2",

src/loader.ts

@@ -1,5 +1,5 @@
 import { existsSync } from "node:fs";
-import { rm } from "node:fs/promises";
+import { readFile, rm } from "node:fs/promises";
 import { homedir } from "node:os";
 import { resolve, extname, dirname, basename, join } from "pathe";
 import createJiti from "jiti";
@@ -47,6 +47,16 @@ export async function loadConfig<
       interopDefault: true,
       requireCache: false,
       esmResolve: true,
+      extensions: [
+        ".js",
+        ".mjs",
+        ".cjs",
+        ".ts",
+        ".mts",
+        ".cts",
+        ".json",
+        ".jsonc",
+      ],
       ...options.jitiOptions,
     });
 
@@ -316,7 +326,12 @@ async function resolveConfig<
   if (!existsSync(res.configFile!)) {
     return res;
   }
-  res.config = options.jiti!(res.configFile!);
+  if (res.configFile!.endsWith(".jsonc")) {
+    const { parse } = await import("jsonc-parser");
+    res.config = parse(await readFile(res.configFile!, "utf8"));
+  } else {
+    res.config = options.jiti!(res.configFile!);
+  }
   if (res.config instanceof Function) {
     res.config = await res.config();
   }

test/fixture/.base/config.jsonc

@@ -0,0 +1,16 @@
+{
+  // jsonc can support comments!
+  "$meta": {
+    "name": "base",
+    "version": "1.0.0",
+  },
+  "baseConfig": true,
+  "colors": {
+    "primary": "base_primary",
+    "text": "base_text",
+  },
+  "array": ["b"],
+  "$env": {
+    "test": { "baseEnvConfig": true },
+  },
+}

test/index.test.ts

@@ -166,7 +166,7 @@ describe("c12", () => {
               "text": "base_text",
             },
           },
-          "configFile": "<path>/fixture/.base/config.ts",
+          "configFile": "<path>/fixture/.base/config.jsonc",
           "cwd": "<path>/fixture/.base",
           "meta": {
             "name": "base",
@@ -276,7 +276,7 @@ describe("c12", () => {
     expect(Object.keys(configLayer.config!)).toContain("$test");
 
     const baseConfigLay = transformdLayers.find(
-      (layer) => layer.configFile === "<path>/fixture/.base/config.ts",
+      (layer) => layer.configFile === "<path>/fixture/.base/config.jsonc",
     )!;
     expect(Object.keys(baseConfigLay.config!)).toContain("$env");
   });