Vue js props值未定义

<template>
  <div>
    <child-component :propName="propValue"></child-component>
  </div>
</template>

<script>
export default {
  data() {
    return {
      propValue: 'Hello World'
    }
  }
}
</script>

<template>
  <div>
    <p>{{ propName }}</p>
  </div>
</template>

<script>
export default {
  props: ['propName']
}
</script>

<template>
  <div>
    <p>{{ propName }}</p>
  </div>
</template>

<script>
export default {
  props: {
    propName: {
      type: String,
      default: 'Default Value'
    }
  }
}
</script>