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/*
* SonarQube
* Copyright (C) 2009-2018 SonarSource SA
* mailto:info AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
import * as React from 'react';
export default class HeadingsLink extends React.Component {
skipScrollingHandler = false;
constructor(props) {
super(props);
this.state = {
activeIndex: -1,
headers: props.headers.filter(
h => h.depth === 2 && h.value.toLowerCase() !== 'table of contents'
)
};
}
componentDidMount() {
document.addEventListener('scroll', this.scrollHandler, true);
}
componentWillReceiveProps(nextProps) {
this.setState({
headers: nextProps.headers.filter(
h => h.depth === 2 && h.value.toLowerCase() !== 'table of contents'
)
});
}
componentWillUnmount() {
document.removeEventListener('scroll', this.scrollHandler, true);
}
highlightHeading = scrollTop => {
let headingIndex = 0;
for (let i = 0; i < this.state.headers.length; i++) {
if (document.querySelector('#header-' + (i + 1)).offsetTop > scrollTop + 40) {
break;
}
headingIndex = i;
}
this.setState({ activeIndex: headingIndex });
this.markH2(headingIndex + 1, false);
};
markH2 = (index, scrollTo) => {
const previousNode = document.querySelector('.targetted-heading');
if (previousNode) {
previousNode.classList.remove('targetted-heading');
}
const node = document.querySelector('#header-' + index);
if (node) {
node.classList.add('targetted-heading');
if (scrollTo) {
this.skipScrollingHandler = true;
window.scrollTo(0, node.offsetTop - 30);
this.highlightHeading(node.offsetTop - 30);
}
}
};
scrollHandler = () => {
if (this.skipScrollingHandler) {
this.skipScrollingHandler = false;
return;
}
const scrollTop = window.pageYOffset | document.body.scrollTop;
this.highlightHeading(scrollTop);
};
clickHandler = target => {
return event => {
event.stopPropagation();
event.preventDefault();
this.markH2(target, true);
};
};
render() {
const { headers } = this.state;
if (headers.length < 1) {
return null;
}
return (
<div className="headings-container">
<ul>
{headers.map((header, index) => {
return (
<li key={index + 1}>
<a
onClick={this.clickHandler(index + 1)}
href={'#header-' + (index + 1)}
className={this.state.activeIndex === index ? 'active' : ''}>
{header.value}
</a>
</li>
);
})}
</ul>
</div>
);
}
}
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