Add strict types

Author: wooorm

index.js

@@ -13,6 +13,7 @@
  */
 
 import {hasProperty} from 'hast-util-has-property'
+// @ts-expect-error: next.
 import minifyWhitespace from 'rehype-minify-whitespace'
 import {convert} from 'unist-util-is'
 import {visit} from 'unist-util-visit'
@@ -50,7 +51,7 @@ export function toMdast(tree, options = {}) {
        * @param {string|Array.<Node>} [children]
        */
       (node, type, props, children) => {
-        /** @type {Properties} */
+        /** @type {Properties|undefined} */
         let properties
 
         if (typeof props === 'string' || Array.isArray(props)) {
@@ -61,7 +62,7 @@ export function toMdast(tree, options = {}) {
         }
 
         /** @type {Node} */
-        // @ts-ignore Assume valid `type` and `children`/`value`.
+        // @ts-expect-error Assume valid `type` and `children`/`value`.
         const result = {type, ...properties}
 
         if (typeof children === 'string') {
@@ -98,7 +99,7 @@ export function toMdast(tree, options = {}) {
 
   minifyWhitespace({newlines: options.newlines === true})(tree)
 
-  const result = one(h, tree, null)
+  const result = one(h, tree, undefined)
 
   if (!result) {
     mdast = {type: 'root', children: []}
@@ -115,6 +116,7 @@ export function toMdast(tree, options = {}) {
   /** @type {import('unist-util-visit').Visitor<Element>} */
   function onelement(node) {
     const id =
+      // @ts-expect-error: `hasProperty` just checked it.
       hasProperty(node, 'id') && String(node.properties.id).toUpperCase()
 
     if (id && !own.call(byId, id)) {
@@ -132,11 +134,15 @@ export function toMdast(tree, options = {}) {
    * @type {import('unist-util-visit').Visitor<Text>}
    */
   function ontext(node, index, parent) {
+    /* c8 ignore next 3 */
+    if (index === null || !parent) {
+      return
+    }
+
     const previous = parent.children[index - 1]
 
-    if (previous && node.type === previous.type) {
+    if (previous && previous.type === node.type) {
       previous.value += node.value
-
       parent.children.splice(index, 1)
 
       if (previous.position && node.position) {
@@ -151,7 +157,7 @@ export function toMdast(tree, options = {}) {
 
     // We don’t care about other phrasing nodes in between (e.g., `[ asd ]()`),
     // as there the whitespace matters.
-    if (block(parent)) {
+    if (parent && block(parent)) {
       if (!index) {
         node.value = node.value.replace(/^[\t ]+/, '')
       }

lib/all.js

@@ -15,7 +15,7 @@ import {one} from './one.js'
  */
 export function all(h, parent) {
   /** @type {Array.<Node>} */
-  // @ts-ignore Assume `parent` is a parent.
+  // @ts-expect-error Assume `parent` is a parent.
   const nodes = parent.children || []
   /** @type {Array.<MdastNode>} */
   let values = []
@@ -24,7 +24,7 @@ export function all(h, parent) {
   let result
 
   while (++index < nodes.length) {
-    // @ts-ignore assume `parent` is a parent.
+    // @ts-expect-error assume `parent` is a parent.
     result = one(h, nodes[index], parent)
 
     if (result) {

lib/handlers/a.js

@@ -1,6 +1,7 @@
 /**
  * @typedef {import('../types.js').Handle} Handle
  * @typedef {import('../types.js').Element} Element
+ * @typedef {import('../types.js').Properties} Properties
  */
 
 import {all} from '../all.js'
@@ -11,12 +12,15 @@ import {resolve} from '../util/resolve.js'
  * @param {Element} node
  */
 export function a(h, node) {
+  /** @type {Properties} */
+  // @ts-expect-error: `props` are defined.
+  const props = node.properties
   return h(
     node,
     'link',
     {
-      title: node.properties.title || null,
-      url: resolve(h, String(node.properties.href || '') || null)
+      title: props.title || null,
+      url: resolve(h, String(props.href || '') || null)
     },
     all(h, node)
   )

lib/handlers/base.js

@@ -9,7 +9,8 @@
  */
 export function base(h, node) {
   if (!h.baseFound) {
-    h.frozenBaseUrl = String(node.properties.href || '') || null
+    h.frozenBaseUrl =
+      String((node.properties && node.properties.href) || '') || null
     h.baseFound = true
   }
 }

lib/handlers/code.js

@@ -4,7 +4,6 @@
  * @typedef {import('../types.js').ElementChild} ElementChild
  */
 
-import {hasProperty} from 'hast-util-has-property'
 import {convertElement} from 'hast-util-is-element'
 import {toText} from 'hast-util-to-text'
 import {trimTrailingLines} from 'trim-trailing-lines'
@@ -24,20 +23,19 @@ const isCode = convertElement('code')
 export function code(h, node) {
   const children = node.children
   let index = -1
-  /** @type {Array.<string|number>} */
+  /** @type {Array.<string|number>|undefined} */
   let classList
-  /** @type {string} */
+  /** @type {string|undefined} */
   let lang
-  /** @type {ElementChild} */
-  let child
 
   if (pre(node)) {
     while (++index < children.length) {
-      child = children[index]
+      const child = children[index]
 
       if (
         isCode(child) &&
-        hasProperty(child, 'className') &&
+        child.properties &&
+        child.properties.className &&
         Array.isArray(child.properties.className)
       ) {
         classList = child.properties.className
@@ -46,7 +44,7 @@ export function code(h, node) {
     }
   }
 
-  if (Array.isArray(classList)) {
+  if (classList) {
     index = -1
 
     while (++index < classList.length) {

lib/handlers/dl.js

@@ -82,6 +82,7 @@ export function dl(h, node) {
       content.push({
         type: 'listItem',
         spread: result.length > 1,
+        // @ts-expect-error: `null` is fine.
         checked: null,
         children: result
       })
@@ -116,6 +117,7 @@ function handle(h, children) {
   }
 
   return [
+    // @ts-expect-error: `null` is fine.
     {
       type: 'list',
       ordered: false,

lib/handlers/iframe.js

@@ -1,6 +1,7 @@
 /**
  * @typedef {import('../types.js').Handle} Handle
  * @typedef {import('../types.js').Element} Element
+ * @typedef {import('../types.js').Properties} Properties
  */
 
 import {resolve} from '../util/resolve.js'
@@ -11,8 +12,11 @@ import {wrapText} from '../util/wrap-text.js'
  * @param {Element} node
  */
 export function iframe(h, node) {
-  const src = String(node.properties.src || '')
-  const title = String(node.properties.title || '')
+  /** @type {Properties} */
+  // @ts-expect-error: `props` are defined.
+  const props = node.properties
+  const src = String(props.src || '')
+  const title = String(props.title || '')
 
   // Only create a link if there is a title.
   // We can’t use the content of the frame because conforming HTML parsers treat
@@ -21,6 +25,7 @@ export function iframe(h, node) {
   if (src && title) {
     return {
       type: 'link',
+      // @ts-expect-error: `null` is fine.
       title: null,
       url: resolve(h, src),
       children: [{type: 'text', value: wrapText(h, title)}]

lib/handlers/img.js

@@ -1,6 +1,7 @@
 /**
  * @typedef {import('../types.js').Handle} Handle
  * @typedef {import('../types.js').Element} Element
+ * @typedef {import('../types.js').Properties} Properties
  */
 
 import {resolve} from '../util/resolve.js'
@@ -10,9 +11,12 @@ import {resolve} from '../util/resolve.js'
  * @param {Element} node
  */
 export function img(h, node) {
+  /** @type {Properties} */
+  // @ts-expect-error: `props` are defined.
+  const props = node.properties
   return h(node, 'image', {
-    url: resolve(h, String(node.properties.src || '') || null),
-    title: node.properties.title || null,
-    alt: node.properties.alt || ''
+    url: resolve(h, String(props.src || '') || null),
+    title: props.title || null,
+    alt: props.alt || ''
   })
 }

lib/handlers/input.js

@@ -1,6 +1,7 @@
 /**
  * @typedef {import('../types.js').Handle} Handle
  * @typedef {import('../types.js').Element} Element
+ * @typedef {import('../types.js').Properties} Properties
  * @typedef {import('../types.js').MdastNode} MdastNode
  */
 
@@ -20,6 +21,8 @@ const datalist = convertElement('datalist')
  */
 // eslint-disable-next-line complexity
 export function input(h, node) {
+  /** @type {Properties} */
+  // @ts-expect-error: `props` are defined.
   const props = node.properties
   let value = String(props.value || props.placeholder || '')
   /** @type {Array.<MdastNode>} */

lib/handlers/li.js

@@ -20,11 +20,11 @@ const input = convertElement('input')
  */
 export function li(h, node) {
   const head = node.children[0]
-  /** @type {boolean} */
+  /** @type {boolean|null} */
   let checked = null
   /** @type {ElementChild} */
   let checkbox
-  /** @type {Element} */
+  /** @type {Element|undefined} */
   let clone
 
   // Check if this node starts with a checkbox.
@@ -33,6 +33,7 @@ export function li(h, node) {
 
     if (
       input(checkbox) &&
+      checkbox.properties &&
       (checkbox.properties.type === 'checkbox' ||
         checkbox.properties.type === 'radio')
     ) {