jquery更多和收起图标怎么不能动了？

$("#more_see").click(function(){
    var $this=$(this);
    if($this.text()=='更多' && $this.hasClass("fa fa-chevron-down")){ //找到收起否则不会执行else语句 ==是相等的
        $this.text('收起').addClass("fa fa-chevron-up");
        alert("收起");
    }else{
        $this.text('更多').removeClass("fa fa-chevron-down");
        alert("更多")
    }
});

<span id="more_see" class="show-out fa-chevron-up">更多</span>

---

$("#more_see").click(function(){

var $this=$(this);
$this.hasClass("fa-chevron-up") ? $this.text('收起').attr("class","fa fa-chevron-down"):
$this.text('收起').attr("class","fa fa-chevron-up");

});

---

$this.hasClass("fa fa-chevron-down")
它的值是true还是false？
可以这样用么？

 $("#more_see").click(function(){
    var $this=$(this);
    console.log($this.hasClass("fa fa-chevron-up"));
    if($this.text()=='更多' && $this.hasClass("fa-chevron-up")){ //找到收起否则不会执行else语句 ==是相等的
        $this.text('收起').removeClass("fa fa-chevron-up").addClass("fa fa-chevron-down");
        alert("收起");
    }else{
        $this.text('更多').removeClass("fa fa-chevron-down").addClass("fa fa-chevron-up");
        alert("更多")
    }
});

HTML

<span id="more_see" class="show-out fa-chevron-up">更多</span>