Improve workspace performance and few other things

src/backend/controllers/hierarchy.js

@@ -65,7 +65,7 @@ const cacheHierarchy = () => {
     const file = allFiles[fileIndex];
     if (file) {
       const cwd = getPath();
-      exec(`git --no-pager log --follow --format="%H" "${file.path}"`, { cwd }, (error, stdout, stderr) => {
+      exec(`git --no-pager log --follow --no-merges --format="%H" "${file.path}"`, { cwd }, (error, stdout, stderr) => {
         if (!error && !stderr) {
           const output = stdout.toString().replace(/\n$/, '');
           const shas = output.split('\n').reverse();
@@ -92,24 +92,22 @@ const getHierarchy = (req, res, next) => {
   res.json({ hierarchy: cachedHierarchy });
 };
 
-const getFile = (req, res, next) => {
-  const { categoryKey, algorithmKey, fileName } = req.params;
+const getAlgorithm = (req, res, next) => {
+  const { categoryKey, algorithmKey } = req.params;
 
   const category = cachedHierarchy.find(category => category.key === categoryKey);
   if (!category) return next(new NotFoundError());
   const algorithm = category.algorithms.find(algorithm => algorithm.key === algorithmKey);
   if (!algorithm) return next(new NotFoundError());
-  const file = algorithm.files.find(file => file.name === fileName);
-  if (!file) return next(new NotFoundError());
 
-  const { content, contributors } = file;
-  res.json({ file: { content, contributors } });
+  const files = algorithm.files.map(({ name, content, contributors }) => ({ name, content, contributors }));
+  res.json({ algorithm: { ...algorithm, files } });
 };
 
 router.route('/')
   .get(getHierarchy);
 
-router.route('/:categoryKey/:algorithmKey/:fileName')
-  .get(getFile);
+router.route('/:categoryKey/:algorithmKey')
+  .get(getAlgorithm);
 
 export default router;
\ No newline at end of file

algorithms @ c9b0606b

-Subproject commit f17c57048f65f287d12e13e6f35b606034aeeb31
+Subproject commit c9b0606bd6c80e02bc12c0215722cbbd9751965e

src/frontend/apis/index.js

@@ -51,7 +51,7 @@ const PUT = URL => {
 
 const HierarchyApi = {
   getHierarchy: GET('/hierarchy'),
-  getFile: GET('/hierarchy/:categoryKey/:algorithmKey/:fileName'),
+  getAlgorithm: GET('/hierarchy/:categoryKey/:algorithmKey'),
 };
 
 const WikiApi = {
@@ -62,6 +62,7 @@ const WikiApi = {
 const GitHubApi = {
   auth: token => gh = new GitHub({ token }),
   getProfile: () => gh.getUser().getProfile(),
+  listGists: () => gh.getUser().listGists(),
 };
 
 export {

src/frontend/common/config.js

-const stepLimit = 1e6;
+const stepLimit = 1e6; // TODO: limit number of traces
+
+const CATEGORY_SCRATCH_PAPER = 'scratch-paper';
+const ALGORITHM_NEW = 'new';
 
 export {
   stepLimit,
+  CATEGORY_SCRATCH_PAPER,
+  ALGORITHM_NEW,
 };
\ No newline at end of file

src/frontend/components/App/index.jsx

@@ -3,7 +3,6 @@ import { connect } from 'react-redux';
 import { loadProgressBar } from 'axios-progress-bar'
 import { CodeEditor, DescriptionViewer, Header, Navigator, ToastContainer, WikiViewer, } from '/components';
 import { Workspace, WSSectionContainer, WSTabContainer } from '/workspace/components';
-import { Section } from '/workspace/core';
 import { actions as toastActions } from '/reducers/toast';
 import { actions as envActions } from '/reducers/env';
 import { GitHubApi, HierarchyApi } from '/apis';
@@ -26,11 +25,21 @@ class App extends React.Component {
   constructor(props) {
     super(props);
 
-    this.spawnReference = Workspace.createReference();
-    this.navigatorReference = Workspace.createReference();
+    this.workspaceRef = React.createRef();
+    this.navigator = null;
+
+    this.state = {
+      files: [],
+      codeFile: null,
+      descFile: null,
+      renderers: [],
+    };
   }
 
   componentDidMount() {
+    const workspace = this.workspaceRef.current;
+    this.navigator = workspace.findSectionById('navigator');
+
     this.updateDirectory(this.props.match.params);
 
     HierarchyApi.getHierarchy()
@@ -45,7 +54,7 @@ class App extends React.Component {
     const { signedIn, accessToken } = this.props.env;
     if (signedIn) GitHubApi.auth(accessToken);
 
-    tracerManager.setOnRender(renderers => this.handleChangeRenderers(renderers));
+    tracerManager.setOnRender(renderers => this.setState({ renderers }));
     tracerManager.setOnError(error => this.props.showErrorToast(error.message));
   }
 
@@ -63,51 +72,37 @@ class App extends React.Component {
   updateDirectory({ categoryKey = null, algorithmKey = null }) {
     if (categoryKey && algorithmKey) {
       this.props.setDirectory(categoryKey, algorithmKey);
+      HierarchyApi.getAlgorithm(categoryKey, algorithmKey)
+        .then(({ algorithm }) => {
+          const { files } = algorithm;
+          const codeFile = files.find(file => file.name === 'code.js') || null;
+          const descFile = files.find(file => file.name === 'desc.md') || null;
+          this.setState({ files, codeFile, descFile });
+        })
+        .catch(() => this.setState({ files: [] }));
     }
   }
 
-  handleChangeRenderers(renderers) {
-    const oldSections = this.rendererSections || {};
-    const newSections = {};
-    for (const renderer of renderers) {
-      const { tracerKey, element } = renderer;
-      let section = null;
-      if (tracerKey in oldSections) {
-        section = oldSections[tracerKey];
-        section.setElement(element);
-        delete oldSections[tracerKey];
-      } else {
-        section = new Section(element);
-        this.spawnReference.core.addChild(section);
-      }
-      newSections[tracerKey] = section;
-    }
-    Object.values(oldSections).forEach(tab => tab.remove());
-    this.rendererSections = newSections;
-  }
-
   render() {
-    const { hierarchy, categoryKey, algorithmKey } = this.props.env;
-
-    const navigatorOpened = true;
+    const { codeFile, descFile, renderers } = this.state;
 
-    return hierarchy && categoryKey && algorithmKey && (
+    return (
       <div className={styles.app}>
-        <Workspace className={styles.workspace} wsProps={{ horizontal: false }}>
+        <Workspace className={styles.workspace} wsProps={{ horizontal: false }} ref={this.workspaceRef}>
           <Header wsProps={{
             removable: false,
             size: 32,
             fixed: true,
             resizable: false,
           }}
-                  onClickTitleBar={() => this.navigatorReference.core.setVisible(!this.navigatorReference.core.visible)}
-                  navigatorOpened={navigatorOpened} />
+                  onClickTitleBar={() => this.navigator.setVisible(!this.navigator.visible)}
+                  navigatorOpened={true /* TODO: fix */} />
           <WSSectionContainer wsProps={{ fixed: true }}>
             <Navigator wsProps={{
+              id: 'navigator',
               removable: false,
               size: 240,
               minSize: 120,
-              reference: this.navigatorReference,
               fixed: true,
             }} />
             <WSTabContainer>
@@ -116,12 +111,13 @@ class App extends React.Component {
                 title: 'Visualization',
                 removable: false,
                 horizontal: false,
-                reference: this.spawnReference
-              }} />
+              }}>
+                {renderers}
+              </WSSectionContainer>
             </WSTabContainer>
             <WSTabContainer>
-              <DescriptionViewer wsProps={{ title: 'Description' }} />
-              <CodeEditor wsProps={{ title: 'code.js' }} />
+              <DescriptionViewer wsProps={{ title: 'Description' }} file={descFile} />
+              <CodeEditor wsProps={{ title: 'code.js' }} file={codeFile} />
             </WSTabContainer>
           </WSSectionContainer>
         </Workspace>

src/frontend/components/App/stylesheet.scss

@@ -15,7 +15,6 @@ body {
   user-select: none;
   color: $color-font;
   font-size: $font-size-normal;
-  background-color: $theme-normal;
 }
 
 a {

src/frontend/components/CodeEditor/index.jsx

 import React from 'react';
 import AceEditor from 'react-ace';
-import { connect } from 'react-redux';
 import 'brace/mode/javascript';
 import 'brace/theme/tomorrow_night_eighties';
+import 'brace/ext/searchbox';
 import { tracerManager } from '/core';
 import { classes } from '/common/util';
 import styles from './stylesheet.scss';
-import { HierarchyApi } from '/apis';
 import { ContributorsViewer } from '/components';
-import { actions as envActions } from '/reducers/env';
 
-// TODO: code should not be reloaded when reopening tab
-@connect(
-  ({ env }) => ({
-    env
-  }), {
-    ...envActions
-  }
-)
 class CodeEditor extends React.Component {
   constructor(props) {
     super(props);
 
+    const { file } = props;
     const { lineIndicator } = tracerManager;
     this.state = {
       lineMarker: this.createLineMarker(lineIndicator),
-      file: null,
+      code: file && file.content,
     };
   }
 
   componentDidMount() {
-    const { categoryKey, algorithmKey } = this.props.env;
-    this.loadFile(categoryKey, algorithmKey);
-
     tracerManager.setOnUpdateLineIndicator(lineIndicator => this.setState({ lineMarker: this.createLineMarker(lineIndicator) }));
   }
 
   componentWillReceiveProps(nextProps) {
-    const { categoryKey, algorithmKey } = nextProps.env;
-    if (categoryKey !== this.props.env.categoryKey ||
-      algorithmKey !== this.props.env.algorithmKey) {
-      this.loadFile(categoryKey, algorithmKey);
+    const { file } = nextProps;
+    if (file !== this.props.file) {
+      this.handleChangeCode(file && file.content);
     }
   }
 
@@ -48,15 +35,6 @@ class CodeEditor extends React.Component {
     tracerManager.setOnUpdateLineIndicator(null);
   }
 
-  loadFile(categoryKey, algorithmKey) {
-    HierarchyApi.getFile(categoryKey, algorithmKey, 'code.js')
-      .then(({ file }) => {
-        this.setState({ file });
-        tracerManager.setCode(file.content);
-      })
-      .catch(() => this.setState({ file: null }));
-  }
-
   createLineMarker(lineIndicator) {
     if (lineIndicator === null) return null;
     const { lineNumber, cursor } = lineIndicator;
@@ -73,14 +51,13 @@ class CodeEditor extends React.Component {
   }
 
   handleChangeCode(code) {
-    const file = { ...this.state.file, content: code };
-    this.setState({ file });
+    this.setState({ code });
     tracerManager.setCode(code);
   }
 
   render() {
-    const { lineMarker, file } = this.state;
-    const { className, relativeWeight } = this.props;
+    const { className, file } = this.props;
+    const { lineMarker, code } = this.state;
 
     return file && (
       <div className={classes(styles.code_editor, className)}>
@@ -92,10 +69,9 @@ class CodeEditor extends React.Component {
           editorProps={{ $blockScrolling: true }}
           onChange={code => this.handleChangeCode(code)}
           markers={lineMarker ? [lineMarker] : []}
-          value={file.content}
-          width={`${relativeWeight}`} />
+          value={code} />
         <ContributorsViewer contributors={file.contributors} />
-      </div> // TODO: trick to update on resize
+      </div> // TODO: need resizing when parent resizes
     );
   }
 }

src/frontend/components/DescriptionViewer/index.jsx

 import React from 'react';
-import { connect } from 'react-redux';
-import { actions as envActions } from '/reducers/env';
-import { HierarchyApi } from '/apis/index';
 import { ContributorsViewer, MarkdownViewer } from '/components';
 import styles from './stylesheet.scss';
 import { classes } from '/common/util';
 
-@connect(
-  ({ env }) => ({
-    env
-  }), {
-    ...envActions
-  }
-)
 class DescriptionViewer extends React.Component {
-  constructor(props) {
-    super(props);
-
-    this.state = {
-      file: null,
-    };
-  }
-
-  componentDidMount() {
-    const { categoryKey, algorithmKey } = this.props.env;
-    const href = `/algorithm/${categoryKey}/${algorithmKey}`;
-    this.loadFile(href);
-  }
-
-  componentWillReceiveProps(nextProps) {
-    const { categoryKey, algorithmKey } = nextProps.env;
-    if (categoryKey !== this.props.env.categoryKey ||
-      algorithmKey !== this.props.env.algorithmKey) {
-      const href = `/algorithm/${categoryKey}/${algorithmKey}`;
-      this.loadFile(href);
-    }
-  }
-
-  loadFile(href) {
-    const [, , categoryKey, algorithmKey] = href.split('/');
-    HierarchyApi.getFile(categoryKey, algorithmKey, 'desc.md')
-      .then(({ file }) => this.setState({ file }))
-      .catch(() => this.setState({ file: null }));
-  }
-
   render() {
-    const { className } = this.props;
-    const { file } = this.state;
+    const { className, file } = this.props;
     return file && (
       <div className={classes(styles.description_viewer, className)}>
-        <MarkdownViewer className={styles.markdown_viewer} source={file.content} onClickLink={href => this.loadFile(href)} />
+        <MarkdownViewer className={styles.markdown_viewer} source={file.content} />
         <ContributorsViewer contributors={file.contributors} />
       </div>
     );

src/frontend/components/Header/index.jsx

@@ -72,15 +72,23 @@ class Header extends React.Component {
     const { className, onClickTitleBar, navigatorOpened } = this.props;
     const { hierarchy, categoryKey, algorithmKey, signedIn } = this.props.env;
 
+    let directory = ['Algorithm Visualizer'];
+    if (hierarchy && categoryKey && algorithmKey) {
       const category = hierarchy.find(category => category.key === categoryKey);
       const algorithm = category.algorithms.find(algorithm => algorithm.key === algorithmKey);
+      directory = [category.name, algorithm.name];
+    }
 
     return (
       <header className={classes(styles.header, className)}>
         <Button className={styles.title_bar} onClick={onClickTitleBar}>
-          <Ellipsis>{category.name}</Ellipsis>
-          <FontAwesomeIcon className={styles.nav_arrow} fixedWidth icon={faAngleRight} />
-          <Ellipsis>{algorithm.name}</Ellipsis>
+          {
+            directory.map((path, i) => [
+              <Ellipsis key={`path-${i}`}>{path}</Ellipsis>,
+              i < directory.length - 1 &&
+              <FontAwesomeIcon className={styles.nav_arrow} fixedWidth icon={faAngleRight} key={`arrow-${i}`} />
+            ])
+          }
           <FontAwesomeIcon className={styles.nav_caret} fixedWidth
                            icon={navigatorOpened ? faCaretDown : faCaretRight} />
         </Button>

src/frontend/components/MarkdownViewer/index.jsx

@@ -8,7 +8,7 @@ class MarkdownViewer extends React.Component {
     const { className, source, onClickLink } = this.props;
 
     const link = ({ href, ...rest }) => {
-      return /^https?:\/\//i.test(href) ? (
+      return !onClickLink || /^https?:\/\//i.test(href) ? (
         <a href={href} rel="noopener" target="_blank" {...rest} />
       ) : (
         <a onClick={() => onClickLink(href)} {...rest} />

src/frontend/components/Navigator/index.jsx

@@ -8,29 +8,44 @@ import faGithub from '@fortawesome/fontawesome-free-brands/faGithub';
 import { ExpandableListItem, ListItem } from '/components';
 import { classes } from '/common/util';
 import { actions as envActions } from '/reducers/env';
+import { actions as toastActions } from '/reducers/toast';
 import styles from './stylesheet.scss';
+import { ALGORITHM_NEW, CATEGORY_SCRATCH_PAPER } from '/common/config';
 
 @connect(
   ({ env }) => ({
     env
   }), {
-    ...envActions
+    ...envActions,
+    ...toastActions,
   }
 )
 class Navigator extends React.Component {
   constructor(props) {
     super(props);
 
-    const { categoryKey } = this.props.env;
-
     this.state = {
-      categoriesOpened: {
-        [categoryKey]: true,
-      },
+      categoriesOpened: {},
+      scratchPaperOpened: false,
+      favoritesOpened: false,
       query: '',
     }
   }
 
+  componentDidMount() {
+    const { categoryKey } = this.props.env;
+    if (categoryKey) {
+      this.toggleCategory(categoryKey, true);
+    }
+  }
+
+  componentWillReceiveProps(nextProps) {
+    const { categoryKey } = nextProps.env;
+    if (categoryKey) {
+      this.toggleCategory(categoryKey, true);
+    }
+  }
+
   toggleCategory(key, categoryOpened = !this.state.categoriesOpened[key]) {
     const categoriesOpened = {
       ...this.state.categoriesOpened,
@@ -39,6 +54,14 @@ class Navigator extends React.Component {
     this.setState({ categoriesOpened });
   }
 
+  toggleScratchPaper(scratchPaperOpened = !this.state.scratchPaperOpened) {
+    this.setState({ scratchPaperOpened });
+  }
+
+  toggleFavorites(favoritesOpened = !this.state.favoritesOpened) {
+    this.setState({ favoritesOpened });
+  }
+
   handleChangeQuery(e) {
     const { hierarchy } = this.props.env;
     const categoriesOpened = {};
@@ -48,7 +71,6 @@ class Navigator extends React.Component {
         categoriesOpened[category.key] = true;
       }
     });
-
     this.setState({ categoriesOpened, query });
   }
 
@@ -58,9 +80,9 @@ class Navigator extends React.Component {
   }
 
   render() {
-    const { categoriesOpened, query } = this.state;
+    const { categoriesOpened, scratchPaperOpened, favoritesOpened, query } = this.state;
     const { className, style } = this.props;
-    const { hierarchy, categoryKey: selectedCategoryKey, algorithmKey: selectedAlgorithmKey } = this.props.env;
+    const { hierarchy, categoryKey, algorithmKey, signedIn } = this.props.env;
 
     return (
       <nav className={classes(styles.navigator, className)} style={style}>
@@ -71,7 +93,7 @@ class Navigator extends React.Component {
         </div>
         <div className={styles.algorithm_list}>
           {
-            hierarchy.map(category => {
+            hierarchy && hierarchy.map(category => {
               const categoryOpened = categoriesOpened[category.key];
               let algorithms = category.algorithms;
               if (!this.testQuery(category.name)) {
@@ -84,7 +106,7 @@ class Navigator extends React.Component {
                                     opened={categoryOpened}>
                   {
                     algorithms.map(algorithm => {
-                      const selected = category.key === selectedCategoryKey && algorithm.key === selectedAlgorithmKey;
+                      const selected = category.key === categoryKey && algorithm.key === algorithmKey;
                       return (
                         <ListItem indent key={algorithm.key} selected={selected}
                                   to={`/${category.key}/${algorithm.key}`} label={algorithm.name} />
@@ -97,9 +119,24 @@ class Navigator extends React.Component {
           }
         </div>
         <div className={styles.footer}>
-          <ExpandableListItem icon={faCode} label="Scratch Paper" />
-          <ExpandableListItem icon={faStar} label="Favorites" />
-          <ListItem icon={faGithub} label="Fork me on GitHub" href="https://github.com/parkjs814/AlgorithmVisualizer" />
+          {
+            signedIn ?
+              <ExpandableListItem icon={faCode} label="Scratch Paper" onClick={() => this.toggleScratchPaper()}
+                                  opened={scratchPaperOpened}>
+                <ListItem indent label="New ..." to={`/${CATEGORY_SCRATCH_PAPER}/${ALGORITHM_NEW}`} />
+              </ExpandableListItem> :
+              <ListItem icon={faCode} label="Scratch Paper"
+                        onClick={() => this.props.showSuccessToast('Sign In Required')} />
+          }
+          {
+            signedIn ?
+              <ExpandableListItem icon={faStar} label="Favorites" onClick={() => this.toggleFavorites()}
+                                  opened={favoritesOpened} /> :
+              <ListItem icon={faStar} label="Favorites"
+                        onClick={() => this.props.showSuccessToast('Sign In Required')} />
+          }
+          <ListItem icon={faGithub} label="Fork me on GitHub"
+                    href="https://github.com/algorithm-visualizer/algorithm-visualizer" />
         </div>
       </nav>
     );

src/frontend/core/tracerManager.jsx

@@ -103,10 +103,9 @@ class TracerManager {
     }[className];
     const data = new DataClass(options);
     this.datas[tracerKey] = data;
-    const renderer = {
-      tracerKey,
-      element: <RendererClass title={title} data={data} wsProps={{ fixed: true }} />
-    };
+    const renderer = (
+      <RendererClass key={tracerKey} title={title} data={data} wsProps={{ fixed: true }} />
+    );
     this.renderers.push(renderer);
   }
 

src/frontend/workspace/components/WSSectionContainer/index.jsx

@@ -9,7 +9,7 @@ class WSSectionContainer extends React.Component {
     super(props);
 
     const { core } = props;
-    core.reference.component = this;
+    core.component = this;
     this.core = core;
   }
 
@@ -57,7 +57,7 @@ class WSSectionContainer extends React.Component {
     visibleChildren.forEach((child, visibleIndex) => {
       const index = children.indexOf(child);
       elements.push(
-        <Divider key={`divider-before-${child.key}`} horizontal={horizontal}
+        <Divider key={`divider-${index}`} horizontal={horizontal}
                  onResize={visibleIndex > 0 && ((target, dx, dy) => this.handleResize(visibleIndex, target, dx, dy))}
                  onDropTab={tab => this.handleDropTabToContainer(tab, index)}
                  onDropSection={section => this.handleDropSectionToContainer(section, index)}
@@ -71,13 +71,13 @@ class WSSectionContainer extends React.Component {
       };
       if (children.length === 1) {
         elements.push(
-          <div key={child.key} className={classes(styles.wrapper)} style={style}>
+          <div key={child.id} className={classes(styles.wrapper)} style={style}>
             {child.element}
           </div>
         );
       } else {
         elements.push(
-          <div key={child.key} className={classes(styles.wrapper, !horizontal && styles.horizontal)} style={style}>
+          <div key={child.id} className={classes(styles.wrapper, !horizontal && styles.horizontal)} style={style}>
             {
               !child.fixed &&
               <Divider horizontal={!horizontal}
@@ -96,7 +96,7 @@ class WSSectionContainer extends React.Component {
       }
       if (visibleIndex === visibleChildren.length - 1) {
         elements.push(
-          <Divider key={`divider-after-${child.key}`} horizontal={horizontal}
+          <Divider key={`divider-last`} horizontal={horizontal}
                    onDropTab={tab => this.handleDropTabToContainer(tab, index + 1)}
                    onDropSection={section => this.handleDropSectionToContainer(section, index + 1)}
                    disableDrop={child.fixed} />

src/frontend/workspace/components/WSTabContainer/index.jsx

@@ -22,7 +22,7 @@ class WSTabContainer extends React.Component {
     super(props);
 
     const { core } = props;
-    core.reference.component = this;
+    core.component = this;
     this.core = core;
   }
 

src/frontend/workspace/components/Workspace/index.jsx

 import React from 'react';
 import { classes } from '/common/util';
 import { WSSectionContainer } from '/workspace/components';
-import { SectionContainer } from '/workspace/core';
+import { Parent, SectionContainer } from '/workspace/core';
 import styles from './stylesheet.scss';
 
 class Workspace extends React.Component {
-  static createReference() {
-    return {
-      core: null,
-      component: null,
-    };
-  }
-
   constructor(props) {
     super(props);
 
-    const { className, children, wsProps } = props;
-    this.sectionContainer = new SectionContainer(
+    this.sectionContainer = new SectionContainer(this.getElement(props));
+  }
+
+  componentDidMount() {
+    this.handleChangeElement(this.props);
+  }
+
+  componentWillReceiveProps(nextProps) {
+    this.handleChangeElement(nextProps);
+  }
+
+  getElement(props) {
+    const { className, wsProps, ...rest } = props;
+    return (
       <WSSectionContainer className={classes(styles.workspace, className)}
-                          wsProps={{ removable: false, ...wsProps }}>
-        {children}
-      </WSSectionContainer>
+                          wsProps={{ id: 'workspace', removable: false, ...wsProps }} {...rest} />
     );
   }
 
+  handleChangeElement(props) {
+    const element = this.getElement(props);
+
+    const unmark = section => {
+      section.updated = false;
+      if (section instanceof Parent) {
+        section.children.forEach(unmark);
+      }
+    };
+    unmark(this.sectionContainer);
+
+    console.log('----');
+    const update = (element, parentSection) => {
+      const { children = [], wsProps = {} } = element.props;
+      const id = wsProps.id || `${parentSection.id}-${element.key}`;
+      if (id.startsWith('workspace-.1-.1-.1-')) console.log(id.slice('workspace-.1-.1-.1-'.length));
+      let section = this.findSectionById(id);
+      if (section) {
+        section.setElement(element);
+      } else {
+        section = parentSection.childify(React.cloneElement(element, { wsProps: { ...wsProps, id } }));
+        parentSection.addChild(section);
+      }
+      section.updated = true;
+      if (section instanceof Parent) {
+        React.Children.toArray(children).forEach(element => update(element, section));
+      }
+    };
+    update(element);
+
+    const removeUnmarked = section => {
+      if (!section.updated) {
+        section.remove();
+      } else if (section instanceof Parent) {
+        section.children.forEach(removeUnmarked);
+      }
+    };
+    removeUnmarked(this.sectionContainer);
+  }
+
+  findSectionById(id, section = this.sectionContainer) {
+    if (section.id === id) return section;
+    if (section instanceof Parent) {
+      for (const childSection of section.children) {
+        const foundSection = this.findSectionById(id, childSection);
+        if (foundSection) return foundSection;
+      }
+    }
+  }
+
   render() {
     return this.sectionContainer.element;
   }

src/frontend/workspace/core/Child.js

-import React from 'react';
-import uuid from 'uuid';
-import { Workspace } from '/workspace/components';
-
-class Child {
-  getDefaultProps() {
-    return {
-      reference: Workspace.createReference(),
-      removable: true,
-    };
-  }
-
-  createElement(wsProps) {
-    return (
-      <div wsProps={wsProps} />
-    );
-  }
-
-  constructor(element) {
-    if (!React.isValidElement(element)) {
-      element = this.createElement(element);
-    }
-    const { wsProps = {} } = element.props;
-    Object.assign(this, this.getDefaultProps(), wsProps);
-    this.reference.core = this;
-    this.key = uuid.v4();
-    this.parent = null;
-    this.init(element);
-  }
-
-  init(element) {
-    this.element = React.cloneElement(element, { core: this });
-  }
-
-  setParent(parent) {
-    if (this.parent) this.remove(true);
-    this.parent = parent;
-  }
-
-  setElement(element) {
-    this.init(element);
-    this.parent.render();
-  }
-
-  remove(moving = false) {
-    if (this.removable || moving) {
-      const index = this.parent.findIndex(this.key);
-      this.parent.removeChild(index);
-    }
-  }
-}
-
-export default Child;
\ No newline at end of file

src/frontend/workspace/core/mixins/parentMixin.js → src/frontend/workspace/core/Parent.js

 import React from 'react';
-import { Child } from '/workspace/core';
+import { Section } from '/workspace/core';
 
-const parentMixin = (Base = Child) => class Parent extends Base {
+class Parent extends Section {
   constructor(element) {
     super(element);
-    const { children = [] } = this.element.props;
     this.children = [];
-    React.Children.forEach(children, element => this.addChild(this.childify(element)));
+  }
+
+  setElement(element) {
+    super.setElement(React.cloneElement(element, { core: this }));
   }
 
   childify(element) {
-    return new Child(element);
+    return new Section(element);
   }
 
-  addChild(child, index = this.children.length, beforeRender) {
+  addChild(child, index = this.children.length) {
     if (child.parent === this) {
       const oldIndex = this.children.indexOf(child);
       this.children[oldIndex] = null;
@@ -23,25 +25,20 @@ const parentMixin = (Base = Child) => class Parent extends Base {
       this.children.splice(index, 0, child);
       child.setParent(this);
     }
-    if(beforeRender) beforeRender();
-    this.render();
   }
 
-  removeChild(index, beforeRender) {
+  removeChild(index) {
     this.children.splice(index, 1);
     if (this.children.length === 0) this.remove();
-    if(beforeRender) beforeRender();
-    this.render();
   }
 
-  findIndex(key) {
-    return this.children.findIndex(child => child.key === key);
+  findIndex(child) {
+    return this.children.indexOf(child);
   }
 
   render() {
-    const { component } = this.reference;
-    if (component) component.forceUpdate();
+    if (this.component) this.component.forceUpdate();
   }
-};
+}
 
-export default parentMixin;
+export default Parent;
\ No newline at end of file

src/frontend/workspace/core/Section.js

-import { Child } from '/workspace/core';
+import React from 'react';
 
-class Section extends Child {
+class Section {
   getDefaultProps() {
     return {
-      ...super.getDefaultProps(),
+      id: null,
+      removable: true,
       visible: true,
       resizable: true,
       weight: 1,
@@ -17,13 +18,37 @@ class Section extends Child {
   }
 
   constructor(element) {
-    super(element);
+    if (!React.isValidElement(element)) {
+      element = this.createElement(element);
+    }
+    this.parent = null;
+    Object.assign(this, this.getDefaultProps());
+    this.setElement(element);
+  }
+
+  createElement(wsProps) {
+    return (
+      <div wsProps={wsProps} />
+    );
+  }
+
+  setElement(element) {
+    const { wsProps = {} } = element.props;
+    Object.assign(this, wsProps);
     this.relative = this.size === -1;
+    this.element = element;
+  }
+
+  setParent(parent) {
+    if (this.parent) this.remove(true);
+    this.parent = parent;
   }
 
-  setVisible(visible) {
-    this.visible = visible;
-    this.parent.render();
+  remove(moving = false) {
+    if (this.removable || moving) {
+      const index = this.parent.findIndex(this);
+      this.parent.removeChild(index);
+    }
   }
 }
 

src/frontend/workspace/core/SectionContainer.js

 import React from 'react';
-import { Section, TabContainer } from '/workspace/core';
-import { parentMixin } from '/workspace/core/mixins';
+import { Parent, Section, TabContainer } from '/workspace/core';
 import { WSSectionContainer, WSTabContainer } from '/workspace/components';
 
-class SectionContainer extends parentMixin(Section) {
+class SectionContainer extends Parent {
   getDefaultProps() {
     return {
       ...super.getDefaultProps(),
@@ -32,7 +31,7 @@ class SectionContainer extends parentMixin(Section) {
     super.removeChild(index);
     if (this.removable && this.children.length === 1) {
       const [child] = this.children;
-      const index = this.parent.findIndex(this.key);
+      const index = this.parent.findIndex(this);
       this.parent.addChild(child, index);
     }
   }

src/frontend/workspace/core/TabContainer.js

 import React from 'react';
-import { Section, Tab } from '/workspace/core';
+import { Parent, Tab } from '/workspace/core';
 import { WSTabContainer } from '/workspace/components';
-import { parentMixin } from '/workspace/core/mixins';
 
-class TabContainer extends parentMixin(Section) {
+class TabContainer extends Parent {
   getDefaultProps() {
     return {
       ...super.getDefaultProps(),
@@ -22,15 +21,13 @@ class TabContainer extends parentMixin(Section) {
   }
 
   addChild(child, index = this.children.length) {
-    super.addChild(child, index, () => {
+    super.addChild(child, index);
     this.setTabIndex(Math.min(index, this.children.length - 1));
-    });
   }
 
   removeChild(index) {
-    super.removeChild(index, () => {
+    super.removeChild(index);
     this.setTabIndex(Math.min(this.tabIndex, this.children.length - 1));
-    });
   }
 
   setTabIndex(tabIndex) {

src/frontend/workspace/core/draggingData.js

-import uuid from 'uuid';
-
-const key = 'dragging-data-id';
-
-class DraggingData {
-  constructor() {
-    this.id = null;
-    this.data = null;
-  }
-
-  set(e, type, child) {
-    this.id = uuid.v4();
-    this.data = { type, child };
-    e.dataTransfer.dropEffect = 'move';
-    e.dataTransfer.setData(key, this.id);
-  }
-
-  get(e) {
-    const id = e.dataTransfer.getData(key);
-    if (id === this.id) return this.data;
-  }
-}
-
-const draggingData = new DraggingData();
-export default draggingData;
\ No newline at end of file

src/frontend/workspace/core/index.js

-export { default as Child } from './Child';
-export { default as draggingData } from './draggingData';
 export { default as Section } from './Section';
+export { default as Parent } from './Parent';
 export { default as SectionContainer } from './SectionContainer';
-export { default as Tab } from './Tab';
 export { default as TabContainer } from './TabContainer';
+export { default as Tab } from './Tab';

src/frontend/workspace/core/mixins/index.js

-export { default as parentMixin } from './parentMixin';
\ No newline at end of file