const convertFromStyle = (style) => { if (style.match(/[0-9](px|rem)/g)) { return Number(style.replace(/[^0-9]/g, '')); } return 0; }; Object.defineProperty(global.HTMLElement.prototype, 'offsetWidth', { get() { return convertFromStyle(this.style.width || '0px'); }, }); Object.defineProperty(global.HTMLElement.prototype, 'offsetHeight', { get() { return convertFromStyle(this.style.height || '0px'); }, });