fix(ts): correctly export sub-module types (#1677)

* chore(types): build types script

Adds a script that moves the declaration files we have in `./types` to `./dist` relative to the files they intend to type.

This is the first step, we still need to change what we declare in `package.json`, add the script to the CI pipeline if we're happy with it and figure out how to type `next-auth/jwt`.

* refactor(lint): fix build-types script

config/build-types.js

@@ -0,0 +1,23 @@
+const fs = require('fs')
+const path = require('path')
+
+const BUILD_TARGETS = [
+  'index.d.ts',
+  'client.d.ts',
+  'adapters.d.ts',
+  'providers.d.ts',
+  'jwt.d.ts',
+  '_next.d.ts',
+  '_utils.d.ts'
+]
+
+BUILD_TARGETS.forEach((target) => {
+  fs.copyFile(
+    path.resolve('types', target),
+    path.join(process.cwd(), target),
+    (err) => {
+      if (err) throw err
+      console.log(`[build-types] copying "${target}" to root folder`)
+    }
+  )
+})

package.json

@@ -7,9 +7,10 @@
   "author": "Iain Collins <me@iaincollins.com>",
   "main": "index.js",
   "scripts": {
-    "build": "npm run build:js && npm run build:css",
+    "build": "npm run build:js && npm run build:css && npm run build:types",
     "build:js": "babel --config-file ./config/babel.config.json src --out-dir dist",
     "build:css": "postcss --config config/postcss.config.js src/**/*.css --base src --dir dist && node config/wrap-css.js",
+    "build:types": "node ./config/build-types.js",
     "dev": "next | npm run watch:css",
     "watch": "npm run watch:js | npm run watch:css",
     "watch:js": "babel --config-file ./config/babel.config.json --watch src --out-dir dist",