docs: introduce JS script to escape for Hexo, fixes #480

bin/escape-nunjucks.js

@@ -0,0 +1,18 @@
+#!/usr/bin/env node
+
+// In Hexo, content inside markdown code/code fences,
+// will not go through nunjucks.
+// So we're escaping special chars outside code only.
+let backTick = 0
+process.stdin.on('data', (buffer) => {
+  for (const c of buffer.toString()) {
+    if (c === '`') {
+      backTick++
+    }
+    const shouldEscape = '{%%}'.includes(c) && backTick % 2 === 0
+    if (shouldEscape) {
+      const code = c.charCodeAt(0).toString(16)
+      process.stdout.write(`&#x${code};`)
+    } else process.stdout.write(c)
+  }
+})