frontend > app

app/components/Editor/components/Contents.js

@@ -0,0 +1,149 @@
+// @flow
+import React, { Component } from 'react';
+import { observable } from 'mobx';
+import { observer } from 'mobx-react';
+import { List } from 'immutable';
+import { color } from 'styles/constants';
+import headingToSlug from '../headingToSlug';
+import type { State, Block } from '../types';
+import styled from 'styled-components';
+
+type Props = {
+  state: State,
+};
+
+@observer class Contents extends Component {
+  props: Props;
+  @observable activeHeading: ?string;
+
+  componentDidMount() {
+    window.addEventListener('scroll', this.updateActiveHeading);
+    this.updateActiveHeading();
+  }
+
+  componentWillUnmount() {
+    window.removeEventListener('scroll', this.updateActiveHeading);
+  }
+
+  updateActiveHeading = () => {
+    const elements = this.headingElements;
+    if (!elements.length) return;
+
+    let activeHeading = elements[0].id;
+
+    for (const element of elements) {
+      const bounds = element.getBoundingClientRect();
+      if (bounds.top <= 0) activeHeading = element.id;
+    }
+
+    this.activeHeading = activeHeading;
+  };
+
+  get headingElements(): HTMLElement[] {
+    const elements = [];
+    const tagNames = ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'];
+
+    for (const tagName of tagNames) {
+      for (const ele of document.getElementsByTagName(tagName)) {
+        elements.push(ele);
+      }
+    }
+
+    return elements;
+  }
+
+  get headings(): List<Block> {
+    const { state } = this.props;
+
+    return state.document.nodes.filter((node: Block) => {
+      if (!node.text) return false;
+      return node.type.match(/^heading/);
+    });
+  }
+
+  render() {
+    // If there are one or less headings in the document no need for a minimap
+    if (this.headings.size <= 1) return null;
+
+    return (
+      <Wrapper>
+        <Sections>
+          {this.headings.map(heading => {
+            const slug = headingToSlug(heading);
+            const active = this.activeHeading === slug;
+
+            return (
+              <ListItem type={heading.type} active={active}>
+                <Anchor href={`#${slug}`} active={active}>
+                  {heading.text}
+                </Anchor>
+              </ListItem>
+            );
+          })}
+        </Sections>
+      </Wrapper>
+    );
+  }
+}
+
+const Wrapper = styled.div`
+  position: fixed;
+  right: 0;
+  top: 150px;
+  z-index: 100;
+`;
+
+const Anchor = styled.a`
+  color: ${props => (props.active ? color.slateDark : color.slate)};
+  font-weight: ${props => (props.active ? 500 : 400)};
+  opacity: 0;
+  transition: all 100ms ease-in-out;
+  margin-right: -5px;
+  padding: 2px 0;
+  pointer-events: none;
+  text-overflow: ellipsis;
+
+  &:hover {
+    color: ${color.primary};
+  }
+`;
+
+const ListItem = styled.li`
+  position: relative;
+  margin-left: ${props => (props.type.match(/heading[12]/) ? '8px' : '16px')};
+  text-align: right;
+  color: ${color.slate};
+  padding-right: 16px;
+  white-space: nowrap;
+
+  &:after {
+    color: ${props => (props.active ? color.slateDark : color.slate)};
+    content: "${props => (props.type.match(/heading[12]/) ? '—' : '–')}";
+    position: absolute;
+    right: 0;
+  }
+`;
+
+const Sections = styled.ol`
+  margin: 0 0 0 -8px;
+  padding: 0;
+  list-style: none;
+  font-size: 13px;
+  width: 100px;
+  transition-delay: 1s;
+  transition: width 100ms ease-in-out;
+
+  &:hover {
+    width: 300px;
+    transition-delay: 0s;
+
+    ${Anchor} {
+      opacity: 1;
+      margin-right: 0;
+      background: ${color.white};
+      pointer-events: all;
+    }
+  }
+`;
+
+export default Contents;