Even though VueJS 2 official documentation about prop validation is stating (as a code example's comment line):

// Basic type check (null and undefined values will pass any type
validation)

I'm getting the following error with this code reproduction — why is that?

[Vue warn]: Invalid prop: type check failed for prop "value". Expected String, Number, Boolean, got Null 

<template>

  <div>

    <h1>{{ title }}:</h1>

    <MyInput :value="null" />

  </div>

</template>



<script>

Vue.component('MyInput', Vue.extend({

  props: {

    value: {

      type: [String, Number, Boolean],

      required: true,

    },

  },

  template: `

    <select v-model="value">

      <option value="null">

        null value

      </option>

      <option value="">

        Empty value

      </option>

    </select>`,

}));



export default {

  data: () => ({

    title: 'VueJS Using Prop Type Validation With NULL and `undefined` Values?'

  }),

};

</script>