Vue实现textarea固定输入行数与添加下划线样式的思路

<textarea class='textarea' @scroll='textsrc' v-model='text.Headquarters' ref='Headquarters' rows="2"></textarea>

textsrc() { 
this.$refs.Headquarters.scrollTo(0, 0) 
let LineNumber = this.$refs.Headquarters.scrollHeight / 35; 
if (LineNumber => 2) { 
this.state = false; 
} else { 
this.state = true; 
}; 
!this.tiemr && !this.state && this.tiemer(); 
this.tiemr && this.state && clearInterval(this.tiemr); 
if (this.state) { 
this.tiemr = null; 
} 
},

tiemer() 
{ 
this.tiemr = setInterval(() => 
{ 
this.text.Headquarters = this.text.Headquarters.slice( 
0, 
this.text.Headquarters.length - 1 
); 
if (this.$refs.Headquarters.scrollHeight / 35 == 2)
{ 
clearInterval(this.tiemr) 
this.tiemr = null 
this.state = true 
}
 },
 10); 
 },