domhandler.ts (from PrimeNG Components) - https://github.com/primefaces/primeng/blob/master/src/app/components/dom/domhandler.ts

domhandler.ts

/**
 * @dynamic is for runtime initializing DomHandler.browser
 *
 * If delete below comment, we can see this error message:
 *  Metadata collected contains an error that will be reported at runtime:
 *  Only initialized variables and constants can be referenced
 *  because the value of this variable is needed by the template compiler.
 */
// @dynamic
export class DomHandler {

    public static zindex: number = 1000;

    private static calculatedScrollbarWidth: number = null;

    private static calculatedScrollbarHeight: number = null;

    private static browser: any;

    public static addClass(element: any, className: string): void {
        if (element.classList)
            element.classList.add(className);
        else
            element.className += ' ' + className;
    }

    public static addMultipleClasses(element: any, className: string): void {
        if (element.classList) {
            let styles: string[] = className.trim().split(' ');
            for (let i = 0; i < styles.length; i++) {
                element.classList.add(styles[i]);
            }

        }
        else {
            let styles: string[] = className.split(' ');
            for (let i = 0; i < styles.length; i++) {
                element.className += ' ' + styles[i];
            }
        }
    }

    public static removeClass(element: any, className: string): void {
        if (element.classList)
            element.classList.remove(className);
        else
            element.className = element.className.replace(new RegExp('(^|\\b)' + className.split(' ').join('|') + '(\\b|$)', 'gi'), ' ');
    }

    public static hasClass(element: any, className: string): boolean {
        if (element.classList)
            return element.classList.contains(className);
        else
            return new RegExp('(^| )' + className + '( |$)', 'gi').test(element.className);
    }

    public static siblings(element: any): any {
        return Array.prototype.filter.call(element.parentNode.children, function (child) {
            return child !== element;
        });
    }

    public static find(element: any, selector: string): any[] {
        return Array.from(element.querySelectorAll(selector));
    }

    public static findSingle(element: any, selector: string): any {
        if (element) {
            return element.querySelector(selector);
        }
        return null;
    }

    public static index(element: any): number {
        let children = element.parentNode.childNodes;
        let num = 0;
        for (var i = 0; i < children.length; i++) {
            if (children[i] == element) return num;
            if (children[i].nodeType == 1) num++;
        }
        return -1;
    }

    public static indexWithinGroup(element: any, attributeName: string): number {
        let children = element.parentNode ? element.parentNode.childNodes : [];
        let num = 0;
        for (var i = 0; i < children.length; i++) {
            if (children[i] == element) return num;
            if (children[i].attributes && children[i].attributes[attributeName] && children[i].nodeType == 1) num++;
        }
        return -1;
    }

    public static relativePosition(element: any, target: any): void {
        let elementDimensions = element.offsetParent ? { width: element.offsetWidth, height: element.offsetHeight } : this.getHiddenElementDimensions(element);
        const targetHeight = target.offsetHeight;
        const targetOffset = target.getBoundingClientRect();
        const viewport = this.getViewport();
        let top: number, left: number;

        if ((targetOffset.top + targetHeight + elementDimensions.height) > viewport.height) {
            top = -1 * (elementDimensions.height);
            element.style.transformOrigin = 'bottom';
            if (targetOffset.top + top < 0) {
                top = -1 * targetOffset.top;
            }
        }
        else {
            top = targetHeight;
            element.style.transformOrigin = 'top';
        }

        if (elementDimensions.width > viewport.width) {
            // element wider then viewport and cannot fit on screen (align at left side of viewport)
            left = targetOffset.left * -1;
        }
        else if ((targetOffset.left + elementDimensions.width) > viewport.width) {
            // element wider then viewport but can be fit on screen (align at right side of viewport)
            left = (targetOffset.left + elementDimensions.width - viewport.width) * -1;
        }
        else {
            // element fits on screen (align with target)
            left = 0;
        }

        element.style.top = top + 'px';
        element.style.left = left + 'px';
    }

    public static absolutePosition(element: any, target: any): void {
        let elementDimensions = element.offsetParent ? { width: element.offsetWidth, height: element.offsetHeight } : this.getHiddenElementDimensions(element);
        let elementOuterHeight = elementDimensions.height;
        let elementOuterWidth = elementDimensions.width;
        let targetOuterHeight = target.offsetHeight;
        let targetOuterWidth = target.offsetWidth;
        let targetOffset = target.getBoundingClientRect();
        let windowScrollTop = this.getWindowScrollTop();
        let windowScrollLeft = this.getWindowScrollLeft();
        let viewport = this.getViewport();
        let top, left;

        if (targetOffset.top + targetOuterHeight + elementOuterHeight > viewport.height) {
            top = targetOffset.top + windowScrollTop - elementOuterHeight;
            element.style.transformOrigin = 'bottom';

            if (top < 0) {
                top = windowScrollTop;
            }
        }
        else {
            top = targetOuterHeight + targetOffset.top + windowScrollTop;
            element.style.transformOrigin = 'top';
        }

        if (targetOffset.left + elementOuterWidth > viewport.width)
            left = Math.max(0, targetOffset.left + windowScrollLeft + targetOuterWidth - elementOuterWidth);
        else
            left = targetOffset.left + windowScrollLeft;

        element.style.top = top + 'px';
        element.style.left = left + 'px';
    }

    static getParents(element: any, parents:any = []): any {
        return element['parentNode'] === null ? parents : this.getParents(element.parentNode, parents.concat([element.parentNode]));
    }

    static getScrollableParents(element: any) {
        let scrollableParents = [];

        if (element) {
            let parents = this.getParents(element);
            const overflowRegex = /(auto|scroll)/;
            const overflowCheck = (node: any) => {
                let styleDeclaration = window['getComputedStyle'](node, null);
                return overflowRegex.test(styleDeclaration.getPropertyValue('overflow')) || overflowRegex.test(styleDeclaration.getPropertyValue('overflowX')) || overflowRegex.test(styleDeclaration.getPropertyValue('overflowY'));
            };

            for (let parent of parents) {
                let scrollSelectors = parent.nodeType === 1 && parent.dataset['scrollselectors'];
                if (scrollSelectors) {
                    let selectors = scrollSelectors.split(',');
                    for (let selector of selectors) {
                        let el = this.findSingle(parent, selector);
                        if (el && overflowCheck(el)) {
                            scrollableParents.push(el);
                        }
                    }
                }
            }
        }

        return scrollableParents;
    }

    public static getHiddenElementOuterHeight(element: any): number {
        element.style.visibility = 'hidden';
        element.style.display = 'block';
        let elementHeight = element.offsetHeight;
        element.style.display = 'none';
        element.style.visibility = 'visible';

        return elementHeight;
    }

    public static getHiddenElementOuterWidth(element: any): number {
        element.style.visibility = 'hidden';
        element.style.display = 'block';
        let elementWidth = element.offsetWidth;
        element.style.display = 'none';
        element.style.visibility = 'visible';

        return elementWidth;
    }

    public static getHiddenElementDimensions(element: any): any {
        let dimensions: any = {};
        element.style.visibility = 'hidden';
        element.style.display = 'block';
        dimensions.width = element.offsetWidth;
        dimensions.height = element.offsetHeight;
        element.style.display = 'none';
        element.style.visibility = 'visible';

        return dimensions;
    }

    public static scrollInView(container, item) {
        let borderTopValue: string = getComputedStyle(container).getPropertyValue('borderTopWidth');
        let borderTop: number = borderTopValue ? parseFloat(borderTopValue) : 0;
        let paddingTopValue: string = getComputedStyle(container).getPropertyValue('paddingTop');
        let paddingTop: number = paddingTopValue ? parseFloat(paddingTopValue) : 0;
        let containerRect = container.getBoundingClientRect();
        let itemRect = item.getBoundingClientRect();
        let offset = (itemRect.top + document.body.scrollTop) - (containerRect.top + document.body.scrollTop) - borderTop - paddingTop;
        let scroll = container.scrollTop;
        let elementHeight = container.clientHeight;
        let itemHeight = this.getOuterHeight(item);

        if (offset < 0) {
            container.scrollTop = scroll + offset;
        }
        else if ((offset + itemHeight) > elementHeight) {
            container.scrollTop = scroll + offset - elementHeight + itemHeight;
        }
    }

    public static fadeIn(element, duration: number): void {
        element.style.opacity = 0;

        let last = +new Date();
        let opacity = 0;
        let tick = function () {
            opacity = +element.style.opacity.replace(",", ".") + (new Date().getTime() - last) / duration;
            element.style.opacity = opacity;
            last = +new Date();

            if (+opacity < 1) {
                (window.requestAnimationFrame && requestAnimationFrame(tick)) || setTimeout(tick, 16);
            }
        };

        tick();
    }

    public static fadeOut(element, ms) {
        var opacity = 1,
            interval = 50,
            duration = ms,
            gap = interval / duration;

        let fading = setInterval(() => {
            opacity = opacity - gap;

            if (opacity <= 0) {
                opacity = 0;
                clearInterval(fading);
            }

            element.style.opacity = opacity;
        }, interval);
    }

    public static getWindowScrollTop(): number {
        let doc = document.documentElement;
        return (window.pageYOffset || doc.scrollTop) - (doc.clientTop || 0);
    }

    public static getWindowScrollLeft(): number {
        let doc = document.documentElement;
        return (window.pageXOffset || doc.scrollLeft) - (doc.clientLeft || 0);
    }

    public static matches(element, selector: string): boolean {
        var p = Element.prototype;
        var f = p['matches'] || p.webkitMatchesSelector || p['mozMatchesSelector'] || p['msMatchesSelector'] || function (s) {
            return [].indexOf.call(document.querySelectorAll(s), this) !== -1;
        };
        return f.call(element, selector);
    }

    public static getOuterWidth(el, margin?) {
        let width = el.offsetWidth;

        if (margin) {
            let style = getComputedStyle(el);
            width += parseFloat(style.marginLeft) + parseFloat(style.marginRight);
        }

        return width;
    }

    public static getHorizontalPadding(el) {
        let style = getComputedStyle(el);
        return parseFloat(style.paddingLeft) + parseFloat(style.paddingRight);
    }

    public static getHorizontalMargin(el) {
        let style = getComputedStyle(el);
        return parseFloat(style.marginLeft) + parseFloat(style.marginRight);
    }

    public static innerWidth(el) {
        let width = el.offsetWidth;
        let style = getComputedStyle(el);

        width += parseFloat(style.paddingLeft) + parseFloat(style.paddingRight);
        return width;
    }

    public static width(el) {
        let width = el.offsetWidth;
        let style = getComputedStyle(el);

        width -= parseFloat(style.paddingLeft) + parseFloat(style.paddingRight);
        return width;
    }

    public static getInnerHeight(el) {
        let height = el.offsetHeight;
        let style = getComputedStyle(el);

        height += parseFloat(style.paddingTop) + parseFloat(style.paddingBottom);
        return height;
    }

    public static getOuterHeight(el, margin?) {
        let height = el.offsetHeight;

        if (margin) {
            let style = getComputedStyle(el);
            height += parseFloat(style.marginTop) + parseFloat(style.marginBottom);
        }

        return height;
    }

    public static getHeight(el): number {
        let height = el.offsetHeight;
        let style = getComputedStyle(el);

        height -= parseFloat(style.paddingTop) + parseFloat(style.paddingBottom) + parseFloat(style.borderTopWidth) + parseFloat(style.borderBottomWidth);

        return height;
    }

    public static getWidth(el): number {
        let width = el.offsetWidth;
        let style = getComputedStyle(el);

        width -= parseFloat(style.paddingLeft) + parseFloat(style.paddingRight) + parseFloat(style.borderLeftWidth) + parseFloat(style.borderRightWidth);

        return width;
    }

    public static getViewport(): any {
        let win = window,
            d = document,
            e = d.documentElement,
            g = d.getElementsByTagName('body')[0],
            w = win.innerWidth || e.clientWidth || g.clientWidth,
            h = win.innerHeight || e.clientHeight || g.clientHeight;

        return { width: w, height: h };
    }

    public static getOffset(el) {
        var rect = el.getBoundingClientRect();

        return {
            top: rect.top + (window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop || 0),
            left: rect.left + (window.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft || 0),
        };
    }

    public static replaceElementWith(element: any, replacementElement: any): any {
        let parentNode = element.parentNode;
        if (!parentNode)
            throw `Can't replace element`;
        return parentNode.replaceChild(replacementElement, element);
    }

    public static getUserAgent(): string {
        return navigator.userAgent;
    }

    public static  isIE() {
        var ua = window.navigator.userAgent;

        var msie = ua.indexOf('MSIE ');
        if (msie > 0) {
            // IE 10 or older => return version number
            return true;
        }

        var trident = ua.indexOf('Trident/');
        if (trident > 0) {
            // IE 11 => return version number
            var rv = ua.indexOf('rv:');
            return true;
        }

        var edge = ua.indexOf('Edge/');
        if (edge > 0) {
           // Edge (IE 12+) => return version number
           return true;
        }

        // other browser
        return false;
    }

    public static isIOS() {
        return /iPad|iPhone|iPod/.test(navigator.userAgent) && !window['MSStream'];
    }

    public static isAndroid() {
        return /(android)/i.test(navigator.userAgent);
    }

    public static appendChild(element: any, target: any) {
        if (this.isElement(target))
            target.appendChild(element);
        else if (target.el && target.el.nativeElement)
            target.el.nativeElement.appendChild(element);
        else
            throw 'Cannot append ' + target + ' to ' + element;
    }

    public static removeChild(element: any, target: any) {
        if (this.isElement(target))
            target.removeChild(element);
        else if (target.el && target.el.nativeElement)
            target.el.nativeElement.removeChild(element);
        else
            throw 'Cannot remove ' + element + ' from ' + target;
    }

    public static removeElement(element: Element) {
        if (!('remove' in Element.prototype))
            element.parentNode.removeChild(element);
        else
            element.remove();
    }

    public static isElement(obj: any) {
        return (typeof HTMLElement === "object" ? obj instanceof HTMLElement :
            obj && typeof obj === "object" && obj !== null && obj.nodeType === 1 && typeof obj.nodeName === "string"
        );
    }

    public static calculateScrollbarWidth(el?: HTMLElement): number {
        if (el) {
            let style = getComputedStyle(el);
            return (el.offsetWidth - el.clientWidth - parseFloat(style.borderLeftWidth) - parseFloat(style.borderRightWidth));
        }
        else {
            if (this.calculatedScrollbarWidth !== null)
                return this.calculatedScrollbarWidth;

            let scrollDiv = document.createElement("div");
            scrollDiv.className = "p-scrollbar-measure";
            document.body.appendChild(scrollDiv);

            let scrollbarWidth = scrollDiv.offsetWidth - scrollDiv.clientWidth;
            document.body.removeChild(scrollDiv);

            this.calculatedScrollbarWidth = scrollbarWidth;

            return scrollbarWidth;
        }
    }

    public static calculateScrollbarHeight(): number {
        if (this.calculatedScrollbarHeight !== null)
            return this.calculatedScrollbarHeight;

        let scrollDiv = document.createElement("div");
        scrollDiv.className = "p-scrollbar-measure";
        document.body.appendChild(scrollDiv);

        let scrollbarHeight = scrollDiv.offsetHeight - scrollDiv.clientHeight;
        document.body.removeChild(scrollDiv);

        this.calculatedScrollbarWidth = scrollbarHeight;

        return scrollbarHeight;
    }

    public static invokeElementMethod(element: any, methodName: string, args?: any[]): void {
        (element as any)[methodName].apply(element, args);
    }

    public static clearSelection(): void {
        if (window.getSelection) {
            if (window.getSelection().empty) {
                window.getSelection().empty();
            } else if (window.getSelection().removeAllRanges && window.getSelection().rangeCount > 0 && window.getSelection().getRangeAt(0).getClientRects().length > 0) {
                window.getSelection().removeAllRanges();
            }
        }
        else if (document['selection'] && document['selection'].empty) {
            try {
                document['selection'].empty();
            } catch(error) {
                //ignore IE bug
            }
        }
    }

    public static getBrowser() {
        if (!this.browser) {
            let matched = this.resolveUserAgent();
            this.browser = {};

            if (matched.browser) {
                this.browser[matched.browser] = true;
                this.browser['version'] = matched.version;
            }

            if (this.browser['chrome']) {
                this.browser['webkit'] = true;
            } else if (this.browser['webkit']) {
                this.browser['safari'] = true;
            }
        }

        return this.browser;
    }

    public static resolveUserAgent() {
        let ua = navigator.userAgent.toLowerCase();
        let match = /(chrome)[ \/]([\w.]+)/.exec(ua) ||
            /(webkit)[ \/]([\w.]+)/.exec(ua) ||
            /(opera)(?:.*version|)[ \/]([\w.]+)/.exec(ua) ||
            /(msie) ([\w.]+)/.exec(ua) ||
            ua.indexOf("compatible") < 0 && /(mozilla)(?:.*? rv:([\w.]+)|)/.exec(ua) ||
            [];

        return {
            browser: match[1] || "",
            version: match[2] || "0"
        };
    }

    public static isInteger(value): boolean {
        if (Number.isInteger) {
            return Number.isInteger(value);
        }
        else {
            return typeof value === "number" && isFinite(value) &&  Math.floor(value) === value;
        }
    }

    public static isHidden(element: HTMLElement): boolean {
        return element.offsetParent === null;
    }

    public static getFocusableElements(element:HTMLElement) {
        let focusableElements = DomHandler.find(element,`button:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]),
                [href][clientHeight][clientWidth]:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]),
                input:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]), select:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]),
                textarea:not([tabindex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]), [tabIndex]:not([tabIndex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden]),
                [contenteditable]:not([tabIndex = "-1"]):not([disabled]):not([style*="display:none"]):not([hidden])`
            );

            let visibleFocusableElements = [];
            for(let focusableElement of focusableElements) {
                if (getComputedStyle(focusableElement).display != "none" && getComputedStyle(focusableElement).visibility != "hidden")
                    visibleFocusableElements.push(focusableElement);
            }
        return visibleFocusableElements;
    }

    static generateZIndex() {
        this.zindex = this.zindex||999;
        return ++this.zindex;
    }
}