Add TypeScript declaration file (`.d.ts`) generation

This is the cleanest way to make a JS library importable to a TS project. This approach is similar to Svelte's approach.

Note the dev dependency on TS is only used for `.d.ts` generation. The source code itself still does not use TS (or any dependencies other than Node.js) at all.

diff --git a/.gitignore b/.gitignore
new file mode 100644 (file)
index 0000000..1d75092
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+node_modules
+types
\ No newline at end of file

diff --git a/package.json b/package.json
index a986620b8e9bf4840cad0d08a6d7ca7834d69eab..36dfb7fca0c6ba2f1d74927c2df1169bf6faa1a0 100644 (file)
--- a/package.json
+++ b/package.json
@@ -10,13 +10,23 @@
     "node": ">=20"
   },
   "files": [
-    "src/*"
+    "./types/*",
+    "./src/*"
   ],
-  "exports": "./src/index.js",
+  "exports": {
+    ".": {
+      "types": "./types/index.d.ts",
+      "default": "./src/index.js"
+    }
+  },
   "scripts": {
+    "types": "tsc ./src/index.js --allowJs --declaration --emitDeclarationOnly --declarationMap --outFile ./types/index.d.ts",
     "test": "node --test --test-skip-pattern=\"/^large:/\"",
     "test:large": "node --test --test-name-pattern=\"/^large:/\"",
     "test:coverage": "npm run test -- --experimental-test-coverage",
     "bench": "node ./benchmark/core.bench.js"
+  },
+  "devDependencies": {
+    "typescript": "^5.8.3"
   }
 }