docs: highlight code

package.json

@@ -27,13 +27,14 @@
     "verror": "^1.8.1"
   },
   "devDependencies": {
-    "eslint": "^7.14.0",
+    "eslint": "^7.20.0",
     "eslint-config-standard": "^16.0.2",
     "eslint-plugin-import": "^2.22.1",
     "eslint-plugin-node": "^11.1.0",
-    "eslint-plugin-promise": "^4.2.1",
+    "eslint-plugin-promise": "^4.3.1",
     "front-matter": "^4.0.2",
     "get-port": "^5.1.1",
+    "highlight.js": "^10.6.0",
     "husky": "^4.2.5",
     "marked": "^2.0.0",
     "tap": "14.11.0"

scripts/build-docs.js

@@ -2,6 +2,16 @@ const fs = require('fs/promises')
 const path = require('path')
 const marked = require('marked')
 const fm = require('front-matter')
+const { highlight, highlightAuto } = require('highlight.js')
+
+marked.use({
+  highlight: (code, lang) => {
+    if (!lang) {
+      return highlightAuto(code).value
+    }
+    return highlight(lang, code).value
+  }
+})
 
 function tocHTML (toc) {
   let html = '<ul>\n'