JSFiddle - React, Tailwind, and code Playground

HTML

<div style="display: none;">
        var ClassB = (function() {
        var method = ClassB.prototype;

        function ClassB( value ) {
            this._value = value;
        }

        method.getValue = function() {
            return this._value;
        };

        method.setValue = function( value ) {
            this._value = value;
        };

        return ClassB;
    })();
    
</div>

JavaScript

var con = document.querySelector("div").textContent;


var r = /([a-zA-Z$_-][a-zA-Z0-9$_-]*)\._.+/g, m;

while( m = r.exec(con)) {
    console.log(m[1] === "this");
}