Changing value in watching cann`t work in some case with Vue - vue.js

Question

I want to change number to int in watch, but it doesn`t work.
index.vue:
<template>
<test v-model="value" />
</template>
<script>
import Test from './test.vue';
export default {
components: {
test: Test,
},
data() {
return {
value: 1,
};
},
watch: {
value(val) {
this.value = parseInt(val);
// this.value = 2;
}
}
};
</script>
test.vue:
<template>
<div class="el-input-number">
<input
:value="currentValue"
#input="handleInput"
ref="input"
/>
</div>
</template>
<script>
export default {
name: 'ElInputNumber',
props: {
value: {
default: 0
},
},
data() {
return {
currentValue: 1
};
},
watch: {
value(value) {
console.log('value change', value);
let newVal = Number(value);
if (isNaN(newVal)) return;
this.currentValue = newVal;
this.$emit('input', newVal);
}
},
computed: {
},
methods: {
setCurrentValue(newVal) {
const oldVal = this.currentValue;
if (oldVal === newVal) return;
this.$emit('change', newVal, oldVal);
this.$emit('input', newVal);
this.currentValue = newVal;
},
handleInput(e) {
const value = e.target.value;
const newVal = Number(value);
if (!isNaN(newVal)) {
this.setCurrentValue(newVal);
}
}
}
};
</script>
The main code is this.value = parseInt(val).
The initial value is 1. I type 1.1 in input. Then I get changes in watching.
After I set this.value, the value watching function isn't called. There is no log.
What's more strange, if I change this.value = parseInt(val) to this.value = 2, it works once, but the second time I change the value, it doesn`t work.
Code is here: https://github.com/lext-7/vue-watch-component-demo.
Run it, and type 1.1 in that input. You will find that it won't become 1.