数组合并与修改

var arr1=['A1','A2','B1','B2','C1','C2'];

var arr2=['A','B','C'];

合并成["A1", "A2", "A", "B1", "B2", "B", "C1", "C2", "C"]

方案一：数组内添加元素并修改元素

var arr1=['A1','A2','B1','B2','C1','C2'];
var arr2=['A','B','C'];
var arr3=arr2.map(item=>item+3);
var arr4=[...arr1,...arr3].sort().map(item=>
         { 
             if(item.includes(3)){
               return(item.split('')[0])
             }
              return item
           }
        )

方案二：插入排序倒序sort -1

var arr1=['A1','A2','B1','B2','C1','C2'];
var arr2=['A','B','C'];
var arr3=arr1.concat(arr2).sort();
arr3.sort((a,b)=>{
  if(a.charAt(0)== b.charAt(0)&&a.length>b.length){
    return -1
  }
})

方案三:数组的修改splice

var arr1=['A1','A2','B1','B2','C1','C2'];
var arr2=['A','B','C'];
arr2.forEach((item,index)=>{arr1.splice((index+1)*2+index,0,item)});