From 7c48947754bce2f881d153eb3c490f2940814c80 Mon Sep 17 00:00:00 2001
From: Pooya Parsa <pyapar@gmail.com>
Date: Thu, 30 Jun 2022 00:17:38 +0200
Subject: [PATCH] feat: try resolving paths as npm package

---
 src/loader.ts                                     | 15 +++++++++++++++
 test/fixture/.gitignore                           |  1 +
 test/fixture/node_modules/c12-npm-test/config.ts  |  3 +++
 .../node_modules/c12-npm-test/package.json        |  7 +++++++
 test/index.test.ts                                |  8 ++++++++
 5 files changed, 34 insertions(+)
 create mode 100644 test/fixture/.gitignore
 create mode 100644 test/fixture/node_modules/c12-npm-test/config.ts
 create mode 100644 test/fixture/node_modules/c12-npm-test/package.json

diff --git a/src/loader.ts b/src/loader.ts
index a9c23a4..db59349 100644
--- a/src/loader.ts
+++ b/src/loader.ts
@@ -153,15 +153,21 @@ async function extendConfig (config, opts: LoadConfigOptions) {
 
 const GIT_PREFIXES = ['github:', 'gitlab:', 'bitbucket:', 'https://']
 
+// https://github.com/dword-design/package-name-regex
+const NPM_PACKAGE_RE = /^(@[a-z0-9-~][a-z0-9-._~]*\/)?[a-z0-9-~][a-z0-9-._~]*$/
+
 const jiti = createJiti(null, { cache: false, interopDefault: true, requireCache: false })
 
 async function resolveConfig (source: string, opts: LoadConfigOptions): Promise<ResolvedConfig> {
+  // Custom user resolver
   if (opts.resolve) {
     const res = await opts.resolve(source, opts)
     if (res) {
       return res
     }
   }
+
+  // Download git URLs and resolve to local path
   if (GIT_PREFIXES.some(prefix => source.startsWith(prefix))) {
     const url = new URL(source)
     const subPath = url.pathname.split('/').slice(2).join('/')
@@ -173,6 +179,15 @@ async function resolveConfig (source: string, opts: LoadConfigOptions): Promise<
     await gittar.extract(tarFile, tmpdir)
     source = resolve(tmpdir, subPath)
   }
+
+  // Try resolving as npm package
+  if (NPM_PACKAGE_RE.test(source)) {
+    try {
+      source = jiti.resolve(source, { paths: [opts.cwd] })
+    } catch (_err) {}
+  }
+
+  // Import from local fs
   const isDir = !extname(source)
   const cwd = resolve(opts.cwd, isDir ? source : dirname(source))
   if (isDir) { source = opts.configFile }
diff --git a/test/fixture/.gitignore b/test/fixture/.gitignore
new file mode 100644
index 0000000..cf4bab9
--- /dev/null
+++ b/test/fixture/.gitignore
@@ -0,0 +1 @@
+!node_modules
diff --git a/test/fixture/node_modules/c12-npm-test/config.ts b/test/fixture/node_modules/c12-npm-test/config.ts
new file mode 100644
index 0000000..b4bb95a
--- /dev/null
+++ b/test/fixture/node_modules/c12-npm-test/config.ts
@@ -0,0 +1,3 @@
+export default {
+  npmConfig: true
+}
diff --git a/test/fixture/node_modules/c12-npm-test/package.json b/test/fixture/node_modules/c12-npm-test/package.json
new file mode 100644
index 0000000..50e4bdc
--- /dev/null
+++ b/test/fixture/node_modules/c12-npm-test/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "c12-npm-test",
+  "version": "0.0.0",
+  "exports": {
+    ".": "./config.ts"
+  }
+}
diff --git a/test/index.test.ts b/test/index.test.ts
index a1cf306..cd736b8 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -40,6 +40,7 @@ describe('c12', () => {
         "configFile": true,
         "defaultConfig": true,
         "devConfig": true,
+        "npmConfig": true,
         "overriden": true,
         "rcFile": true,
         "virtual": true,
@@ -117,6 +118,13 @@ describe('c12', () => {
           "configFile": "<path>/fixture/config.dev.ts",
           "cwd": "<path>/fixture",
         },
+        {
+          "config": {
+            "npmConfig": true,
+          },
+          "configFile": "<path>/fixture/node_modules/c12-npm-test/config.ts",
+          "cwd": "<path>/fixture/node_modules/c12-npm-test",
+        },
       ]
     `)
   })