Fix changing of input tree

Author: wooorm

lib/index.js

@@ -26,12 +26,18 @@ import {createState} from './state.js'
  *   mdast tree.
  */
 export function toMdast(tree, options) {
+  // We have to clone, cause we’ll use `rehype-minify-whitespace` on the tree,
+  // which modifies
+  /** @type {Node} */
+  const cleanTree = JSON.parse(JSON.stringify(tree))
   const options_ = options || {}
   const state = createState(options_)
   /** @type {MdastNode | MdastRoot} */
   let mdast
 
-  visit(tree, function (node) {
+  // @ts-expect-error: does return a transformer, that does accept any node.
+  rehypeMinifyWhitespace({newlines: options_.newlines === true})(cleanTree)
+  visit(cleanTree, function (node) {
     if (node && node.type === 'element' && node.properties) {
       const id = String(node.properties.id || '') || undefined
 
@@ -41,11 +47,7 @@ export function toMdast(tree, options) {
     }
   })
 
-  // To do: clone the tree.
-  // @ts-expect-error: does return a transformer, that does accept any node.
-  rehypeMinifyWhitespace({newlines: options_.newlines === true})(tree)
-
-  const result = state.one(tree, undefined)
+  const result = state.one(cleanTree, undefined)
 
   if (!result) {
     mdast = {type: 'root', children: []}

lib/util/resolve.js

@@ -1,5 +1,5 @@
 /**
- * @typedef {import('../state.js').State} State
+ * @typedef {import('../types.js').State} State
  */
 
 /**