import isBrowser from './isBrowser';
/**
 * 获取DOM元素的style
 * @param {HTMLElement} el dom元素
 * @param {String} prop 样式属性
 * @returns {String|Array<IKeyValue<String>>}
 */
export default function getStyle (el: any, prop: string|undefined): string|undefined|CSSStyleDeclaration {
    if (!el || !isBrowser()) {
        return;
    }
    let _res: CSSStyleDeclaration|string|undefined;
    if (window.getComputedStyle instanceof Function) {
        _res = window.getComputedStyle(el, null);
    } else {
        _res = el.currentStyle;
    }
    if (_res && prop) {
        _res = _res[prop];
    }
    return _res;
}