Add JSDoc based types

Author: wooorm

.gitignore

@@ -1,4 +1,5 @@
 .DS_Store
+*.d.ts
 *.log
 .nyc_output/
 coverage/

index.js

@@ -1,4 +1,9 @@
-// Remove final newline characters from `value`.
+/**
+ * Remove final newline characters from `value`.
+ *
+ * @param {unknown} value Value with trailing line feeds, coerced to string.
+ * @return {string} Value without trailing newlines.
+ */
 export function trimTrailingLines(value) {
   return String(value).replace(/\n+$/, '')
 }

package.json

@@ -23,22 +23,30 @@
   "sideEffects": false,
   "type": "module",
   "main": "index.js",
+  "types": "index.d.ts",
   "files": [
+    "index.d.ts",
     "index.js"
   ],
   "devDependencies": {
-    "c8": "^7.6.0",
+    "@types/tape": "^4.0.0",
+    "c8": "^7.0.0",
     "prettier": "^2.0.0",
     "remark-cli": "^9.0.0",
     "remark-preset-wooorm": "^8.0.0",
+    "rimraf": "^3.0.0",
     "tape": "^5.0.0",
+    "typescript": "^4.0.0",
     "xo": "^0.38.0"
   },
   "scripts": {
+    "prepublishOnly": "npm run build && npm run format",
+    "prebuild": "rimraf \"*.d.ts\"",
+    "build": "tsc",
     "format": "remark . -qfo && prettier . -w --loglevel warn && xo --fix",
     "test-api": "node test.js",
     "test-coverage": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 --reporter lcov node test.js",
-    "test": "npm run format && npm run test-coverage"
+    "test": "npm run build && npm run format && npm run test-coverage"
   },
   "prettier": {
     "tabWidth": 2,

tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "files": ["index.js"],
+  "include": ["*.js"],
+  "compilerOptions": {
+    "target": "ES2020",
+    "lib": ["ES2020"],
+    "module": "ES2020",
+    "moduleResolution": "node",
+    "allowJs": true,
+    "checkJs": true,
+    "declaration": true,
+    "emitDeclarationOnly": true,
+    "allowSyntheticDefaultImports": true,
+    "skipLibCheck": true
+  }
+}