with password component

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/accounting.js/0.4.1/accounting.min.js"></script>
<script src="https://unpkg.com/vue/dist/vue.js"></script>

<div id="app">
  <passoword v-model="pass"></passoword>
  <pre>post = {{pass}}</pre>
</div>

JavaScript

Vue.component('passoword', {
  template: `
    	<input type="text" v-model="localVar"  @keyup="addPass">
		`,
  props: ['value'],
  data: function() {
    return {
      localVar: this.value,
      pw: ''
    }
  },
  methods: {
    addPass: function(event) {
    	let keyCode = event.keyCode; 
			
			if (keyCode >= 48 && keyCode <= 57) {
				let LocalVal = this.value + event.key
        this.pw = LocalVal; 
        this.$emit('input', this.pw)
        let s = "";
        for (let i = 0; i <= LocalVal.length; i++) {
          s += "***";
        }
        this.localVar = s
      }
      
    }
  }
})

new Vue({
  el: '#app',
  data: {
    pass: ''
  },
  created: function() {}
})