vue js passing data through global event bus not working - vuejs2

Question

Using vue cli I have created a simple vue app with two nested components. I want to pass data between them clicking the h1 tag in my component 1 (a more structured approach suggests to use vuex but this is a very easy app passing simple data using for test).
Clicking the h1 I receive an error but I'm not getting the point. The error says
[Vue warn]: Error in event handler for "titleChanged": "TypeError: Cannot read property 'apply' of undefined"
(found in <Root>)
My code is below
main.js
import Vue from 'vue'
import App from './App.vue'
import Axios from 'axios'
Vue.config.productionTip = false
Vue.prototype.$http = Axios
export const bus = new Vue();
new Vue({
render: h => h(App),
}).$mount('#app')
app.vue
<template>
<div>
<comp-1 v-bind:title="title"></comp-1>
<comp-2 v-bind:title="title"></comp-2>
</div>
</template>
<script>
import comp-1 from './components/Comp-1.vue'
import comp-2 from './components/Comp-2.vue'
export default {
components: {
'comp-1': comp-1,
'comp-2': comp-2
},
data() {
return {
title: "my title"
}
}
}
</script>
<style scoped>
</style>
comp-1.vue
<template>
<header>
<h1 v-on:click="changeTitle">{{ pTitle }}</h1>
</header>
</template>
<script>
import {bus} from '../main'
export default {
props: {
title: {
Type: String
}
},
data() {
return {
pTitle: ''
}
},
created: function() {
this.pTitle = this.title
},
methods: {
changeTitle: function() {
this.pTitle = 'I have changed my title!'
bus.$emit('titleChanged', this.pTitle)
}
}
}
</script>
<style scoped>
</style>
comp-2.vue
<template>
<footer>
<p>{{ title }}</p>
</footer>
</template>
<script>
import {bus} from '../main'
export default {
props: {
title: {
Type: String
}
},
data() {
return {
pTitle: ''
}
},
created() {
this.pTitle = this.title;
bus.$on('titleChanged'), (data) => {
this.title = data
}
}
}
</script>
<style scoped>
</style>

Answer 1

In created of comp-2 component, there is a mistake in event handler
Change it like this:
bus.$on("titleChanged", data => {
this.title = data;
});