watcher_component.vue

<template>
  <div></div>
</template>

<script type="text/javascript">
export default {
  props: {
    propId: {
      type: Number,
      required: true
    }
  },
  methods: {
    consoleLogValue(value) {
      console.log(value)
    }
  },
  watch: {
    propId (newVal) {
      this.consoleLogValue(newVal)
    }
  },
}
</script>