JSFiddle - React, Tailwind, and code Playground

HTML

<div class="text-container">
   Test, only one line.

    </div>
    <div class="show-more">
        <a href="#">Show more</a>
    </div>
</div>

CSS

div.text-container {
    margin: 0 auto;
    width: 75%;    
}

.hideContent {
    overflow: hidden;
    line-height: 1em;
    height: 2em;
}

.showContent {
    line-height: 1em;
    height: auto;
}
.showContent{
    height: auto;
}

h1 {
    font-size: 24px;        
}
p {
    padding: 10px 0;
}
.show-more {
    padding: 10px 0;
    text-align: center;
}

JavaScript

$(".show-more a").on("click", function() {
    var $this = $(this); 
    var $content = $this.parent().prev("div.content");
    var linkText = $this.text().toUpperCase();    
    
    if(linkText === "SHOW MORE"){
        linkText = "Show less";
        $content.switchClass("hideContent", "showContent", 400);
    } else {
        linkText = "Show more";
        $content.switchClass("showContent", "hideContent", 400);
    };

    $this.text(linkText);
});