chore(TypeScript): demo for typescript

demo/nodejs/index.js

@@ -4,9 +4,23 @@ const engine = new Liquid({
   root: __dirname,
   extname: '.liquid'
 })
+
+engine.registerTag('header', {
+  parse: function (token) {
+    const [key, val] = token.args.split(':')
+    this[key] = val
+  },
+  render: function (scope, hash) {
+    const title = this.liquid.evalValue(this.content, scope)
+    return `<h1>${title}</h1>`
+  }
+})
+
 const ctx = {
   todos: ['fork and clone', 'make it better', 'make a pull request'],
   title: 'Welcome to liquidjs!'
 }
 
-engine.renderFile('todolist', ctx).then(console.log)
+engine.renderFile('todolist', ctx)
+  .then(console.log)
+  .catch(err => console.error(err.stack))