锚点scrollIntoView遇到固定头部掩盖

解决方案：

参考了JSScrollIntoView插件，运用其核心代码解决此问题。

第一步、方法复制到项目中

/**
 * 
 * @param {*} elem 滚动的元素
 * @param {*} options 滚动配置
 */
function scrollIntoView(elem, options) {
    options = {
        ...options,
        duration: 1000,
        offset: heander.value.clientHeight,
        ease: 'ease-out'
    }
 
    var scrollOffset = elem.getBoundingClientRect().top - options.offset,
        totalScrollOffset = window.scrollY + scrollOffset,
        duration = options.duration,
        startTime = Date.now(),
        distance,
        currentScrollPosition;
 
    requestAnimationFrame(function anim() {
        currentScrollPosition = window.scrollY;
        distance = totalScrollOffset - currentScrollPosition;
 
        var elapsed = Date.now() - startTime;
        var progress = Math.min(1, elapsed / duration);
 
        window.scrollTo(0, currentScrollPosition + (distance * progress));
 
        if (progress < 1 && distance !== 0) {
            requestAnimationFrame(anim);
        }
    });
}

第二步、调用方法

scrollIntoView(elem,options)