probably the idea is to get the dragged content in put, then save it as a field, determine whether the field exists in the boxes on both sides, and display a dotted frame where the content is the field you saved, and then clear the field in the end function. Notice to set .sortable-chosen the display of this class to none

template code has not changed, the click event has been modified, and the idea is the same as what the master on the first floor said: first add elements to the array push on the opposite side, and then delete elements by splice. (the addition and deletion of the vue array are in my notes.) all this work is done by indexing index

 /*  */
            joinHasContents: function(index){
                //this.dom = event.currentTarget;
                this.follow_nohas_contents.push({name: this.follow_has_contents[index].name}); // 
                this.follow_has_contents.splice(index,1);
            },
            joinNoHasContents: function(index){
                //this.dom = event.currentTarget;
                this.follow_has_contents.push({name: this.follow_nohas_contents[index].name}); // 
                this.follow_nohas_contents.splice(index,1);
            }