Add JSDoc based types

Author: wooorm

.gitignore

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

index.js

@@ -1,3 +1,22 @@
+/**
+ * @typedef {Parent['children'][number]|Root} Node
+ * @typedef {import('mdast').Parent} Parent
+ * @typedef {import('mdast').Literal} Literal
+ * @typedef {import('mdast').Root} Root
+ * @typedef {import('mdast').List} List
+ * @typedef {import('mdast').ListItem} ListItem
+ * @typedef {import('mdast').Heading} Heading
+ * @typedef {import('mdast').Code} Code
+ * @typedef {import('mdast').FootnoteDefinition} FootnoteDefinition
+ * @typedef {import('mdast').Definition} Definition
+ * @typedef {import('mdast').Link} Link
+ * @typedef {import('mdast').Image} Image
+ * @typedef {import('mdast').LinkReference} LinkReference
+ * @typedef {import('mdast').ImageReference} ImageReference
+ * @typedef {import('mdast').FootnoteReference} FootnoteReference
+ * @typedef {import('mdast').Table} Table
+ */
+
 import nodeAssert from 'assert'
 import {zwitch} from 'zwitch'
 import {mapz} from 'mapz'
@@ -85,10 +104,19 @@ var mdast = zwitch('type', {
 
 var all = mapz(mdast, {key: 'children'})
 
+/**
+ * @param {unknown} node
+ * @param {Parent} [ancestor]
+ * @returns {asserts node is Node}
+ */
 function unknown(node, ancestor) {
   unistAssert(node, ancestor)
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is Parent}
+ */
 function assertParent(node) {
   unistParent(node)
   all(node)
@@ -107,12 +135,21 @@ function assertLiteral(node) {
   )
 }
 
+/**
+ * @param {unknown} node
+ * @param {Parent} ancestor
+ * @returns {asserts node is Root}
+ */
 function root(node, ancestor) {
   parent(node)
 
   nodeAssert.strictEqual(ancestor, undefined, '`root` should not have a parent')
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is List}
+ */
 function list(node) {
   parent(node)
 
@@ -144,6 +181,10 @@ function list(node) {
   }
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is ListItem}
+ */
 function listItem(node) {
   parent(node)
 
@@ -164,13 +205,21 @@ function listItem(node) {
   }
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is Heading}
+ */
 function heading(node) {
   parent(node)
 
   nodeAssert.ok(node.depth > 0, '`depth` should be gte `1`')
   nodeAssert.ok(node.depth <= 6, '`depth` should be lte `6`')
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is Code}
+ */
 function code(node) {
   literal(node)
 
@@ -192,6 +241,10 @@ function code(node) {
   }
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is FootnoteDefinition}
+ */
 function footnoteDefinition(node) {
   parent(node)
 
@@ -210,6 +263,10 @@ function footnoteDefinition(node) {
   }
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is Definition}
+ */
 function definition(node) {
   _void(node)
 
@@ -238,6 +295,10 @@ function definition(node) {
   }
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is Link}
+ */
 function link(node) {
   parent(node)
 
@@ -252,6 +313,10 @@ function link(node) {
   }
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is Image}
+ */
 function image(node) {
   _void(node)
 
@@ -270,6 +335,10 @@ function image(node) {
   }
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is LinkReference}
+ */
 function linkReference(node) {
   parent(node)
 
@@ -289,13 +358,18 @@ function linkReference(node) {
 
   if (node.referenceType != null) {
     nodeAssert.notStrictEqual(
+      // @ts-expect-error Check if it’s a string.
       ['shortcut', 'collapsed', 'full'].indexOf(node.referenceType),
       -1,
       '`referenceType` must be `shortcut`, `collapsed`, or `full`'
     )
   }
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is ImageReference}
+ */
 function imageReference(node) {
   _void(node)
 
@@ -319,13 +393,18 @@ function imageReference(node) {
 
   if (node.referenceType != null) {
     nodeAssert.notStrictEqual(
+      // @ts-expect-error Check if it’s a string.
       ['shortcut', 'collapsed', 'full'].indexOf(node.referenceType),
       -1,
       '`referenceType` must be `shortcut`, `collapsed`, or `full`'
     )
   }
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is FootnoteReference}
+ */
 function footnoteReference(node) {
   _void(node)
 
@@ -344,20 +423,29 @@ function footnoteReference(node) {
   }
 }
 
+/**
+ * @param {unknown} node
+ * @returns {asserts node is Table}
+ */
 function table(node) {
   var index = -1
+  /** @type {Array.<unknown>} */
+  var align
+  /** @type {unknown} */
   var value
 
   parent(node)
 
   if (node.align != null) {
     nodeAssert.ok(Array.isArray(node.align), '`align` must be `array`')
+    align = node.align // type-coverage:ignore-line
 
-    while (++index < node.align.length) {
-      value = node.align[index]
+    while (++index < align.length) {
+      value = align[index]
 
       if (value != null) {
         nodeAssert.notStrictEqual(
+          // @ts-expect-error Check if it’s a string.
           ['left', 'right', 'center'].indexOf(value),
           -1,
           "each align in table must be `null, 'left', 'right', 'center'`"

index.test-d.ts

@@ -0,0 +1,18 @@
+import {expectType, expectNotType} from 'tsd'
+import {Parent} from 'mdast'
+import {Node, assert, parent} from './index.js'
+
+var emptyNode = {type: 'doctype'}
+var literalNode = {type: 'text', value: 'a'}
+var parentNode = {type: 'element', children: [emptyNode, literalNode]}
+
+expectNotType<Node>(emptyNode)
+expectNotType<Node>(literalNode)
+expectNotType<Node>(parentNode)
+
+assert(emptyNode)
+expectType<Node>(emptyNode)
+
+expectNotType<Parent>(parentNode)
+parent(parentNode)
+expectType<Parent>(parentNode)

package.json

@@ -26,27 +26,37 @@
   "sideEffects": false,
   "type": "module",
   "main": "index.js",
+  "types": "index.d.ts",
   "files": [
+    "index.d.ts",
     "index.js"
   ],
   "dependencies": {
+    "@types/mdast": "^3.0.3",
     "mapz": "^2.0.0",
     "unist-util-assert": "^3.0.0",
     "zwitch": "^2.0.0"
   },
   "devDependencies": {
+    "@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",
+    "tsd": "^0.14.0",
+    "type-coverage": "^2.0.0",
+    "typescript": "^4.0.0",
     "xo": "^0.39.0"
   },
   "scripts": {
+    "prepack": "npm run build && npm run format",
+    "build": "rimraf \"{test/**,}*.d.ts\" && tsc && tsd && type-coverage",
     "format": "remark . -qfo && prettier . -w --loglevel warn && xo --fix",
     "test-api": "node test/index.js",
     "test-coverage": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 --reporter lcov node test/index.js",
-    "test": "npm run format && npm run build && npm run test-coverage"
+    "test": "npm run build && npm run format && npm run build && npm run test-coverage"
   },
   "prettier": {
     "tabWidth": 2,
@@ -59,6 +69,7 @@
   "xo": {
     "prettier": true,
     "rules": {
+      "capitalized-comments": "off",
       "eqeqeq": "off",
       "no-eq-null": "off",
       "no-var": "off",
@@ -69,5 +80,10 @@
     "plugins": [
       "preset-wooorm"
     ]
+  },
+  "typeCoverage": {
+    "atLeast": 100,
+    "detail": true,
+    "strict": true
   }
 }

tsconfig.json

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