| // Licensed to the Apache Software Foundation (ASF) under one or more |
| // contributor license agreements. See the NOTICE file distributed with |
| // this work for additional information regarding copyright ownership. |
| // The ASF licenses this file to You under the Apache License, Version 2.0 |
| // (the "License"); you may not use this file except in compliance with |
| // the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| const rightNav = document.querySelector('.right-nav .sectlevel1') |
| |
| if (IntersectionObserver && rightNav) { |
| const tocAnchors = [...rightNav.querySelectorAll('a[href]')] |
| let last; |
| tocAnchors.forEach((a, i, all) => { |
| const target = document.querySelector(`${a.hash}`) |
| if (!target) return |
| const observer = new IntersectionObserver((entries) => { |
| entries.forEach(entry => { |
| a.classList.toggle('visible', entry.isIntersecting) |
| if (entry.isIntersecting) last = a |
| |
| const firstVisible = rightNav.querySelector('.visible') |
| tocAnchors.forEach(a => a.classList.remove('active')) |
| if (firstVisible) firstVisible.classList.add('active') |
| else if (last) last.classList.add('active') |
| }) |
| }); |
| observer.observe(target) |
| }) |
| } |
