add types definition

add typescript as dev dependency and use it to generate type definition
files in dist/ folder.
fix #7

package.json

@@ -13,6 +13,7 @@
   "main": "dist/dropzone.js",
   "module": "dist/dropzone.mjs",
   "standalone": "dist/dropzone-min.js",
+  "types": "dist/dropzone.d.ts",
   "browserslist": "defaults, > 0.25%",
   "targets": {
     "main": {
@@ -38,7 +39,7 @@
   ],
   "scripts": {
     "watch": "parcel watch",
-    "build": "parcel build && yarn run css",
+    "build": "parcel build && yarn run css && tsc",
     "css": "yarn sass src/:dist/ --style compressed",
     "watch-css": "yarn sass src/:dist/ --watch --style compressed",
     "test": "karma start test/karma.conf.js",
@@ -72,6 +73,7 @@
     "parcel": "^2.0.0",
     "sass": "^1.33.0",
     "sinon": "^11.1.2",
-    "sinon-chai": "^3.5.0"
+    "sinon-chai": "^3.5.0",
+    "typescript": "^5.4.5"
   }
 }

tsconfig.json

@@ -0,0 +1,10 @@
+{
+  "include": ["src/**/*"],
+  "compilerOptions": {
+    "allowJs": true,
+    "declaration": true,
+    "emitDeclarationOnly": true,
+    "declarationMap": true,
+    "outDir": "dist"
+  }
+}

yarn.lock

@@ -3871,6 +3871,11 @@ type-is@~1.6.18:
     media-typer "0.3.0"
     mime-types "~2.1.24"
 
+typescript@^5.4.5:
+  version "5.4.5"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-5.4.5.tgz#42ccef2c571fdbd0f6718b1d1f5e6e5ef006f611"
+  integrity sha512-vcI4UpRgg81oIRUFwR0WSIHKt11nJ7SAVlYNIu+QpqeyXP+gpQJy/Z4+F0aGxSE4MqwjyXvW/TzgkLAx2AGHwQ==
+
 ua-parser-js@^0.7.30:
   version "0.7.37"
   resolved "https://registry.yarnpkg.com/ua-parser-js/-/ua-parser-js-0.7.37.tgz#e464e66dac2d33a7a1251d7d7a99d6157ec27832"