Add JSDoc based types

.gitignore

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

index.js

@@ -1,5 +1,21 @@
-export function bail(error) {
-  if (error) {
-    throw error
+// prettier-ignore
+/**
+ * Throw a given error.
+ *
+ * @type {{
+ *   (error: Error): never
+ *   (error: null | undefined): void
+ *   (): void
+ * }} */
+export var bail = (
+  /**
+   * Throw a given error.
+   *
+   * @param {Error?} [error]
+   */
+  function (error) {
+    if (error) {
+      throw error
+    }
   }
-}
+)

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",
+    "type-coverage": "^2.0.0",
+    "typescript": "^4.0.0",
     "xo": "^0.38.0"
   },
   "scripts": {
+    "prepack": "npm run build && npm run format",
+    "build": "rimraf \"*.d.ts\" && tsc && type-coverage",
     "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,
@@ -51,6 +59,7 @@
   "xo": {
     "prettier": true,
     "rules": {
+      "import/no-mutable-exports": "off",
       "no-var": "off",
       "prefer-arrow-callback": "off"
     }
@@ -59,5 +68,10 @@
     "plugins": [
       "preset-wooorm"
     ]
+  },
+  "typeCoverage": {
+    "atLeast": 100,
+    "detail": true,
+    "strict": true
   }
 }

readme.md

@@ -21,7 +21,7 @@ npm install bail
 ## Use
 
 ```js
-var bail = require('bail')
+import {bail} from 'bail'
 
 bail()
 

test.js

@@ -6,7 +6,16 @@ test('bail([err])', function (t) {
     bail()
   })
 
+  t.doesNotThrow(function () {
+    bail(null)
+  })
+
+  t.doesNotThrow(function () {
+    bail(undefined)
+  })
+
   t.throws(function () {
+    // @ts-ignore
     bail('foo')
   }, /foo/)
 

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
+  }
+}