Merge pull request #4008 from lison16/anchor

anchor-link组件添加scroll-offset属性，会优先使用anchor-link的这个值

src/components/anchor/anchor-link.vue

@@ -1,6 +1,6 @@
 <template>
 	<div :class="anchorLinkClasses">
-        <a :class="linkTitleClasses" :href="href" :data-href="href" @click.prevent="goAnchor" :title="title">{{ title }}</a>
+        <a :class="linkTitleClasses" :href="href" :data-scroll-offset="scrollOffset" :data-href="href" @click.prevent="goAnchor" :title="title">{{ title }}</a>
         <slot></slot>
     </div>
 </template>
@@ -10,7 +10,13 @@ export default {
     inject: ['anchorCom'],
     props: {
         href: String,
-        title: String
+        title: String,
+        scrollOffset: {
+            type: Number,
+            default () {
+                return this.anchorCom.scrollOffset
+            }
+        }
     },
     data () {
         return {

src/components/anchor/anchor.vue

@@ -95,8 +95,14 @@ export default {
         },
         handleScrollTo () {
             const anchor = document.getElementById(this.currentId);
+            const currentLinkElementA = document.querySelector(`a[data-href="${this.currentLink}"]`);
+            let offset = this.scrollOffset;
+            if (currentLinkElementA) {
+                offset = parseFloat(currentLinkElementA.getAttribute('data-scroll-offset'));
+            }
+
             if (!anchor) return;
-            const offsetTop = anchor.offsetTop - this.wrapperTop - this.scrollOffset;
+            const offsetTop = anchor.offsetTop - this.wrapperTop - offset;
             this.animating = true;
             scrollTop(this.scrollContainer, this.scrollElement.scrollTop, offsetTop, 600, () => {
                 this.animating = false;