Add JSDoc based types

Author: wooorm

.gitignore

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

index.js

@@ -1,16 +1,40 @@
+/**
+ * @typedef {import('unist').Node} Node
+ * @typedef {import('unist').Parent} Parent
+ *
+ * @typedef {import('unist-util-is').Type} Type
+ * @typedef {import('unist-util-is').Props} Props
+ * @typedef {import('unist-util-is').TestFunctionAnything} TestFunctionAnything
+ */
+
 import {convert} from 'unist-util-is'
 
+/** @type {Array.<Node>} */
+var empty
+
+/**
+ * @param {Node} node
+ * @param {null|undefined|Type|Props|TestFunctionAnything|Array<Type|Props|TestFunctionAnything>} [test]
+ * @returns {number}
+ */
 export function size(node, test) {
   var is = convert(test)
+
   return fastSize(node)
 
+  /**
+   * @param {Node} node
+   */
   function fastSize(node) {
-    var children = node && node.children
+    /** @type {Array.<Node>} */
+    // @ts-ignore Looks like a parent.
+    var children = (node && node.children) || empty
     var count = 0
     var index = -1
 
     if (children && children.length > 0) {
       while (++index < children.length) {
+        // @ts-ignore Looks like a parent.
         if (is(children[index], index, node)) count++
         count += fastSize(children[index])
       }

package.json

@@ -25,26 +25,35 @@
   "sideEffects": false,
   "type": "module",
   "main": "index.js",
+  "types": "index.d.ts",
   "files": [
+    "index.d.ts",
     "index.js"
   ],
   "dependencies": {
+    "@types/unist": "^2.0.0",
     "unist-util-is": "^5.0.0"
   },
   "devDependencies": {
+    "@types/tape": "^4.0.0",
     "c8": "^7.0.0",
     "hastscript": "^6.0.0",
     "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,
@@ -65,5 +74,10 @@
     "plugins": [
       "preset-wooorm"
     ]
+  },
+  "typeCoverage": {
+    "atLeast": 100,
+    "detail": true,
+    "strict": true
   }
 }

tsconfig.json

@@ -0,0 +1,15 @@
+{
+  "include": ["*.js"],
+  "compilerOptions": {
+    "target": "ES2020",
+    "lib": ["ES2020"],
+    "module": "ES2020",
+    "moduleResolution": "node",
+    "allowJs": true,
+    "checkJs": true,
+    "declaration": true,
+    "emitDeclarationOnly": true,
+    "allowSyntheticDefaultImports": true,
+    "skipLibCheck": true
+  }
+}