core/packages/vue/examples/composition/markdown.html

<script src="../../../../node_modules/marked/marked.min.js"></script>
<script src="../../../../node_modules/lodash/lodash.min.js"></script>
<script src="../../dist/vue.global.js"></script>

<div id="editor">
  <textarea :value="input" @input="update"></textarea>
  <div v-html="output"></div>
</div>

<script>
const delay = window.location.hash === '#test' ? 16 : 300
const { ref, computed } = Vue

const App = {
  setup() {
    const input = ref('# hello')
    const output = computed(() => marked(input.value, { sanitize: true }))
    const update = _.debounce(e => { input.value = e.target.value }, delay)

    return {
      input,
      output,
      update
    }
  }
}

Vue.createApp().mount(App, '#editor')
</script>

<style>
html, body, #editor {
  margin: 0;
  height: 100%;
  font-family: 'Helvetica Neue', Arial, sans-serif;
  color: #333;
}

textarea, #editor div {
  display: inline-block;
  width: 49%;
  height: 100%;
  vertical-align: top;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  padding: 0 20px;
}

textarea {
  border: none;
  border-right: 1px solid #ccc;
  resize: none;
  outline: none;
  background-color: #f6f6f6;
  font-size: 14px;
  font-family: 'Monaco', courier, monospace;
  padding: 20px;
}

code {
  color: #f66;
}
</style>