<template>
  <div>
    <div contenteditable @input="setThought($event.target.innerText)">
      {{ thought }}
    </div>
    <div>
      <button @click="readMind">What is B thinking?</button> {{ otherThought }}
    </div>
  </div>
</template>

<script>
export default {
  name: "ComponentA",
  data() {
    return {
      thought: 'I should steal a cookie',
      otherThought: '',
    };
  },
  methods: {
    setThought(value) {
      this.thought = value;
    },
    readMind() { }
  },
};
</script>