Vue实现textarea固定输入行数与添加下划线样式的思

<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);  
 },