JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<h4>Some Content</h4>
<p>Lorem ipsum dolor sit amet, <b>consectetur</b> adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>

JavaScript

(function(){

    var highlighter = {

        color: 'rgba(255,255,131,.5)',

        /**
         *
         */
        init: function(){
            this.bindEvents();
        },

        /**
         *
         */
        bindEvents: function(){
            // $(document).on('mousedown', this.clearHighlight.bind(this));
            $(document).on('mouseup',   this.emittHighlight.bind(this));
        },

        /**
         *
         */
        emittHighlight: function(){
            var range       = window.getSelection().getRangeAt(0);
            var node        = range.startContainer
            var startOffset = range.startOffset
            var endOffset   = range.endOffset
            var text        = node.parentNode.textContent;
            this.buildRange(text, startOffset, endOffset);
        },

        /**
         *
         */
        buildRange: function(text, startOffset, endOffset){
            var node = this.getNodeByText(text); // get the Node by its contents

            var range = document.createRange();
            range.setStart(node, startOffset);
            range.setEnd(node, endOffset);

            span = document.createElement('span');
            span.style.backgroundColor = this.color;
            $(span).addClass('hl');
            range.surroundContents(span);
        },

        // /**
        //  *
        //  */
        // clearHighlight: function(e){
        //     $('.hl').contents().unwrap();
        // },
        /**
         *
         */
        getNodeByText: function(text){
            var all = document.getElementsByTagName("*");
            for (var i = 0; i < all.length; i++) {
                if (all[i].textContent === text) {
                    return all[i];
                }

            }
        },
    };
    highlighter.init();


})();