Make old paragraph bookmarks forward to the 3rd edition

Author: marijnh

src/client/ejs.mjs

@@ -339,4 +339,17 @@ function debounce(fn, delay = 50) {
   }
 }
 
-if (window.page && /^chapter|hints$/.test(window.page.type)) chapterInteraction()
+if (window.page && /^chapter|hints$/.test(window.page.type)) {
+  chapterInteraction()
+  // 3rd-edition-style anchor
+  let {hash} = document.location
+  if (/^#[phic]_./.test(hash)) {
+    let exists = document.getElementById(hash.replace(/_/, "-"))
+    if (exists) {
+      document.location.hash = hash.replace(/_/, "-")
+    } else {
+      let chapter = /\/[^\/]+\.html/.exec(document.location)
+      if (chapter) document.location = `https://eloquentjavascript.net/3rd_edition${chapter[0]}${hash}`
+    }
+  }
+}

src/transform.mjs

@@ -112,11 +112,11 @@ export function transformTokens(tokens, options) {
       i += 2
     } else {
       if (type == "paragraph_open")
-        tok.hashID = "p_" + hash(startAndEnd(childrenText(tokens[i + 1])))
+        tok.hashID = "p-" + hash(startAndEnd(childrenText(tokens[i + 1])))
       else if (type == "heading_open")
-        tok.hashID = (tok.tag == "h2" ? "h_" : "i_") + hash(childrenText(tokens[i + 1]))
+        tok.hashID = (tok.tag == "h2" ? "h-" : "i-") + hash(childrenText(tokens[i + 1]))
       else if (type == "fence")
-        tok.hashID = "c_" + hash(tok.content)
+        tok.hashID = "c-" + hash(tok.content)
 
       if (tok.children) tok.children = transformInline(tok.children, options, tokens[i - 1].type)