Merge pull request #3332 from overleaf/pr-new-log-entries-ui

New log entries ui

GitOrigin-RevId: a13ccac04197e7c8f3777750b956d550c95c8f0d

services/web/app/views/project/editor/pdf.pug

@@ -19,6 +19,7 @@ div.full-size.pdf(ng-controller="PdfController")
 			output-files="pdf.outputFiles"
 			pdf-download-url="pdf.downloadUrl"
 			show-logs="shouldShowLogs"
+			on-log-entry-link-click="openInEditor"
 		)
 	else
 		.toolbar.toolbar-pdf(ng-class="{ 'changes-to-autocompile': changesToAutoCompile && !autoCompileLintingError }")
@@ -172,7 +173,7 @@ div.full-size.pdf(ng-controller="PdfController")
 					) #{translate("failed_compile_check_ignore")}
 					| .
 
-			div(ng-repeat="entry in pdf.logEntries.all", ng-controller="PdfLogEntryController")
+			div(ng-repeat="entry in pdf.logEntries.all")
 				.alert(
 					ng-class="{\
 						'alert-danger':  entry.level == 'error',\

services/web/frontend/extracted-translation-keys.json

@@ -1,40 +1,43 @@
 [
-  "download_pdf",
+  "auto_compile",
+  "collapse",
+  "compile_mode",
+  "compiling",
   "download_file",
-  "n_warnings",
-  "n_warnings_plural",
-  "n_errors",
-  "n_errors_plural",
+  "download_pdf",
+  "expand",
+  "fast",
   "file_outline",
-  "the_file_outline_is_a_new_feature_click_the_icon_to_learn_more",
-  "we_cant_find_any_sections_or_subsections_in_this_file",
   "find_out_more_about_the_file_outline",
-  "expand",
-  "collapse",
-  "show_outline",
   "hide_outline",
-  "compiling",
-  "recompile",
-  "auto_compile",
-  "on",
-  "off",
-  "other_output_files",
-  "compile_mode",
-  "normal",
-  "fast",
-  "stop_on_validation_error",
   "ignore_validation_errors",
-  "run_syntax_check_now",
   "loading",
+  "log_entry_description",
+  "log_hint_extra_info",
+  "n_errors_plural",
+  "n_errors",
+  "n_warnings_plural",
+  "n_warnings",
+  "navigate_log_source",
   "no_messages",
+  "normal",
+  "off",
+  "on",
+  "other_output_files",
+  "recompile_from_scratch",
+  "recompile",
+  "run_syntax_check_now",
+  "run_syntax_check_now",
   "send_first_message",
+  "show_outline",
+  "stop_on_validation_error",
+  "the_file_outline_is_a_new_feature_click_the_icon_to_learn_more",
+  "toggle_compile_options_menu",
   "toggle_output_files_list",
-  "your_message",
-  "your_project_has_errors",
-  "view_warnings",
   "view_logs",
   "view_pdf",
-  "recompile_from_scratch",
-  "run_syntax_check_now",
-  "toggle_compile_options_menu"
+  "view_warnings",
+  "we_cant_find_any_sections_or_subsections_in_this_file",
+  "your_message",
+  "your_project_has_errors"
 ]

services/web/frontend/js/features/preview/components/preview-log-entry.js

@@ -1,41 +1,178 @@
 import React from 'react'
 import PropTypes from 'prop-types'
 import classNames from 'classnames'
+import { useTranslation } from 'react-i18next'
+import useExpandCollapse from '../../../shared/hooks/use-expand-collapse'
 import Icon from '../../../shared/components/icon'
 
-function PreviewLogEntry({ file, line, message, content, raw, level }) {
-  const logEntryClasses = classNames('alert', {
-    'alert-danger': level === 'error',
-    'alert-warning': level === 'warning',
-    'alert-info': level === 'typesetting'
+function PreviewLogEntry({
+  file,
+  line,
+  message,
+  content,
+  column,
+  humanReadableHintComponent,
+  extraInfoURL,
+  level,
+  onLogEntryLinkClick
+}) {
+  const { t } = useTranslation()
+  function handleLogEntryLinkClick() {
+    onLogEntryLinkClick({ file, line, column })
+  }
+  const logEntryDescription = t('log_entry_description', {
+    level: level
   })
   return (
-    <div className={logEntryClasses}>
-      <span className="line-no">
-        <Icon type="link" />
-        {file ? <span>{file}</span> : null}
-        {line ? <span>, {line}</span> : null}
-      </span>
-      {message ? (
-        <p className="entry-message">
-          {level} {message}
-        </p>
+    <div className="log-entry" aria-label={logEntryDescription}>
+      <PreviewLogEntryHeader
+        level={level}
+        file={file}
+        line={line}
+        message={message}
+        onLogEntryLinkClick={handleLogEntryLinkClick}
+      />
+      {content ? (
+        <PreviewLogEntryContent
+          content={content}
+          humanReadableHintComponent={humanReadableHintComponent}
+          extraInfoURL={extraInfoURL}
+        />
       ) : null}
-      {content ? <p className="entry-content">{content.trim()}</p> : null}
     </div>
   )
 }
 
+function PreviewLogEntryHeader({
+  level,
+  file,
+  line,
+  message,
+  onLogEntryLinkClick
+}) {
+  const { t } = useTranslation()
+  const logEntryHeaderClasses = classNames('log-entry-header', {
+    'log-entry-header-error': level === 'error',
+    'log-entry-header-warning': level === 'warning',
+    'log-entry-header-typesetting': level === 'typesetting'
+  })
+  const headerLinkBtnTitle = t('navigate_log_source', {
+    location: file + (line ? `, ${line}` : '')
+  })
+  return (
+    <header className={logEntryHeaderClasses}>
+      <h3 className="log-entry-header-title">{message}</h3>
+      {file ? (
+        <button
+          className="btn-inline-link log-entry-header-link"
+          type="button"
+          title={headerLinkBtnTitle}
+          onClick={onLogEntryLinkClick}
+        >
+          <Icon type="chain" />
+          &nbsp;
+          <span>{file}</span>
+          {line ? <span>, {line}</span> : null}
+        </button>
+      ) : null}
+    </header>
+  )
+}
+
+function PreviewLogEntryContent({
+  content,
+  humanReadableHintComponent,
+  extraInfoURL
+}) {
+  const { isExpanded, expandableProps, toggleProps } = useExpandCollapse({
+    collapsedSize: 150,
+    classes: {
+      container: 'log-entry-content-raw-expandable-container'
+    }
+  })
+  const logContentClasses = classNames('log-entry-content-raw', {
+    'log-entry-content-raw-collapsed': !isExpanded
+  })
+  const buttonContainerClasses = classNames(
+    'log-entry-content-button-container',
+    {
+      'log-entry-content-button-container-collapsed': !isExpanded
+    }
+  )
+  const { t } = useTranslation()
+
+  return (
+    <div className="log-entry-content">
+      <div {...expandableProps}>
+        <pre className={logContentClasses}>{content.trim()}</pre>
+        <div className={buttonContainerClasses}>
+          <button
+            type="button"
+            className="btn btn-xs btn-default log-entry-btn-expand-collapse"
+            {...toggleProps}
+          >
+            {isExpanded ? (
+              <>
+                <Icon type="angle-up" /> {t('collapse')}
+              </>
+            ) : (
+              <>
+                <Icon type="angle-down" /> {t('expand')}
+              </>
+            )}
+          </button>
+        </div>
+      </div>
+      {humanReadableHintComponent ? (
+        <div className="log-entry-human-readable-hint">
+          {humanReadableHintComponent}
+        </div>
+      ) : null}
+      {extraInfoURL ? (
+        <div className="log-entry-human-readable-hint-link">
+          <a
+            href={extraInfoURL}
+            target="_blank"
+            className="log-entry-human-readable-hint-link"
+          >
+            {t('log_hint_extra_info')}
+          </a>
+        </div>
+      ) : null}
+    </div>
+  )
+}
+
+PreviewLogEntryHeader.propTypes = {
+  level: PropTypes.string.isRequired,
+  file: PropTypes.string,
+  line: PropTypes.any,
+  message: PropTypes.string,
+  onLogEntryLinkClick: PropTypes.func.isRequired
+}
+
+PreviewLogEntryContent.propTypes = {
+  content: PropTypes.string.isRequired,
+  humanReadableHintComponent: PropTypes.oneOfType([
+    PropTypes.arrayOf(PropTypes.node),
+    PropTypes.element
+  ]),
+  extraInfoURL: PropTypes.string
+}
+
 PreviewLogEntry.propTypes = {
   file: PropTypes.string,
   // `line should be either a number or null (i.e. not required), but currently sometimes we get
   // an empty string (from BibTeX errors), which is why we're using `any` here. We should revert
   // to PropTypes.number (not required) once we fix that.
   line: PropTypes.any,
+  column: PropTypes.any,
   message: PropTypes.string,
   content: PropTypes.string,
-  raw: PropTypes.string,
-  level: PropTypes.string.isRequired
+  humanReadableHintComponent: PropTypes.node,
+  extraInfoURL: PropTypes.string,
+  level: PropTypes.oneOf(['error', 'warning', 'typesetting']).isRequired,
+  onLogEntryLinkClick: PropTypes.func.isRequired
 }
 
 export default PreviewLogEntry

services/web/frontend/js/features/preview/components/preview-logs-pane.js

@@ -2,12 +2,16 @@ import React from 'react'
 import PropTypes from 'prop-types'
 import PreviewLogEntry from './preview-log-entry'
 
-function PreviewLogsPane({ logEntries }) {
+function PreviewLogsPane({ logEntries, onLogEntryLinkClick }) {
   return (
-    <div className="pdf-logs">
+    <div className="logs-pane">
       {logEntries && logEntries.length > 0 ? (
         logEntries.map((logEntry, idx) => (
-          <PreviewLogEntry key={idx} {...logEntry} />
+          <PreviewLogEntry
+            key={idx}
+            {...logEntry}
+            onLogEntryLinkClick={onLogEntryLinkClick}
+          />
         ))
       ) : (
         <div>No logs</div>
@@ -17,7 +21,8 @@ function PreviewLogsPane({ logEntries }) {
 }
 
 PreviewLogsPane.propTypes = {
-  logEntries: PropTypes.array
+  logEntries: PropTypes.array,
+  onLogEntryLinkClick: PropTypes.func.isRequired
 }
 
 export default PreviewLogsPane

services/web/frontend/js/features/preview/components/preview-pane.js

@@ -15,10 +15,10 @@ function PreviewPane({
   onToggleLogs,
   outputFiles,
   pdfDownloadUrl,
+  onLogEntryLinkClick,
   showLogs
 }) {
   const { t } = useTranslation()
-
   const nErrors =
     compilerState.logEntries && compilerState.logEntries.errors
       ? compilerState.logEntries.errors.length
@@ -59,7 +59,10 @@ function PreviewPane({
           : ''}
       </span>
       {showLogs ? (
-        <PreviewLogsPane logEntries={compilerState.logEntries.all} />
+        <PreviewLogsPane
+          logEntries={compilerState.logEntries.all}
+          onLogEntryLinkClick={onLogEntryLinkClick}
+        />
       ) : null}
     </>
   )
@@ -74,6 +77,7 @@ PreviewPane.propTypes = {
     logEntries: PropTypes.object.isRequired
   }),
   onClearCache: PropTypes.func.isRequired,
+  onLogEntryLinkClick: PropTypes.func.isRequired,
   onRecompile: PropTypes.func.isRequired,
   onRunSyntaxCheckNow: PropTypes.func.isRequired,
   onSetAutoCompile: PropTypes.func.isRequired,

services/web/frontend/js/ide/pdf/controllers/PdfController.js

@@ -878,6 +878,25 @@ App.controller('PdfController', function(
       $scope.recompile({ check: true })
     })
   }
+
+  $scope.openInEditor = function(entry) {
+    let column, line
+    eventTracking.sendMBOnce('logs-jump-to-location-once')
+    const entity = ide.fileTreeManager.findEntityByPath(entry.file)
+    if (entity == null || entity.type !== 'doc') {
+      return
+    }
+    if (entry.line != null) {
+      line = entry.line
+    }
+    if (entry.column != null) {
+      column = entry.column
+    }
+    ide.editorManager.openDoc(entity, {
+      gotoLine: line,
+      gotoColumn: column
+    })
+  }
 })
 
 App.factory('synctex', function(ide, $http, $q) {
@@ -1048,27 +1067,6 @@ App.controller('PdfSynctexController', function($scope, synctex, ide) {
   }
 })
 
-App.controller('PdfLogEntryController', function($scope, ide, eventTracking) {
-  $scope.openInEditor = function(entry) {
-    let column, line
-    eventTracking.sendMBOnce('logs-jump-to-location-once')
-    const entity = ide.fileTreeManager.findEntityByPath(entry.file)
-    if (entity == null || entity.type !== 'doc') {
-      return
-    }
-    if (entry.line != null) {
-      line = entry.line
-    }
-    if (entry.column != null) {
-      column = entry.column
-    }
-    ide.editorManager.openDoc(entity, {
-      gotoLine: line,
-      gotoColumn: column
-    })
-  }
-})
-
 App.controller('ClearCacheModalController', function($scope, $modalInstance) {
   $scope.state = { error: false, inflight: false }
 

services/web/frontend/js/shared/hooks/use-expand-collapse.js

@@ -0,0 +1,55 @@
+import { useRef, useState, useLayoutEffect } from 'react'
+import classNames from 'classnames'
+
+function useExpandCollapse({
+  initiallyExpanded = false,
+  collapsedSize = '0',
+  dimension = 'height',
+  classes = {}
+} = {}) {
+  const ref = useRef()
+  const [isExpanded, setIsExpanded] = useState(initiallyExpanded)
+  const [size, setSize] = useState()
+
+  useLayoutEffect(
+    () => {
+      const expandCollapseEl = ref.current
+      if (isExpanded) {
+        const expandedSize =
+          dimension === 'height'
+            ? expandCollapseEl.scrollHeight
+            : expandCollapseEl.scrollWidth
+        setSize(expandedSize)
+      } else {
+        setSize(collapsedSize)
+      }
+    },
+    [isExpanded]
+  )
+
+  const expandableClasses = classNames(
+    'expand-collapse-container',
+    classes.container,
+    !isExpanded ? classes.containerCollapsed : null
+  )
+
+  function handleToggle() {
+    setIsExpanded(!isExpanded)
+  }
+
+  return {
+    isExpanded,
+    expandableProps: {
+      ref,
+      style: {
+        [dimension === 'height' ? 'height' : 'width']: `${size}px`
+      },
+      className: expandableClasses
+    },
+    toggleProps: {
+      onClick: handleToggle
+    }
+  }
+}
+
+export default useExpandCollapse

services/web/frontend/stories/preview-log-entry.stories.js

@@ -0,0 +1,117 @@
+import React from 'react'
+import PreviewLogEntry from '../js/features/preview/components/preview-log-entry.js'
+
+export const ErrorWithCompilerOutput = args => <PreviewLogEntry {...args} />
+ErrorWithCompilerOutput.args = {
+  level: 'error'
+}
+
+export const ErrorWithCompilerOutputAndHumanReadableHint = args => (
+  <PreviewLogEntry {...args} />
+)
+ErrorWithCompilerOutputAndHumanReadableHint.args = {
+  level: 'error',
+  humanReadableHintComponent: <SampleHumanReadableHintComponent />,
+  extraInfoURL:
+    'https://www.overleaf.com/learn/latex/Errors/Extra_alignment_tab_has_been_changed_to_%5Ccr'
+}
+
+export const ErrorWithoutCompilerOutput = args => <PreviewLogEntry {...args} />
+ErrorWithoutCompilerOutput.args = {
+  level: 'error',
+  content: null
+}
+
+export const WarningWithCompilerOutput = args => <PreviewLogEntry {...args} />
+WarningWithCompilerOutput.args = {
+  level: 'warning'
+}
+
+export const WarningWithCompilerOutputAndHumanReadableHint = args => (
+  <PreviewLogEntry {...args} />
+)
+WarningWithCompilerOutputAndHumanReadableHint.args = {
+  level: 'warning',
+  humanReadableHintComponent: <SampleHumanReadableHintComponent />,
+  extraInfoURL:
+    'https://www.overleaf.com/learn/latex/Errors/Extra_alignment_tab_has_been_changed_to_%5Ccr'
+}
+
+export const WarningWithoutCompilerOutput = args => (
+  <PreviewLogEntry {...args} />
+)
+WarningWithoutCompilerOutput.args = {
+  level: 'warning',
+  content: null
+}
+
+export const InfoWithCompilerOutput = args => <PreviewLogEntry {...args} />
+InfoWithCompilerOutput.args = {
+  level: 'typesetting'
+}
+
+export const InfoWithCompilerOutputAndHumanReadableHint = args => (
+  <PreviewLogEntry {...args} />
+)
+InfoWithCompilerOutputAndHumanReadableHint.args = {
+  level: 'typesetting',
+  humanReadableHintComponent: <SampleHumanReadableHintComponent />,
+  extraInfoURL:
+    'https://www.overleaf.com/learn/latex/Errors/Extra_alignment_tab_has_been_changed_to_%5Ccr'
+}
+
+export const InfoWithoutCompilerOutput = args => <PreviewLogEntry {...args} />
+InfoWithoutCompilerOutput.args = {
+  level: 'typesetting',
+  content: null
+}
+
+function SampleHumanReadableHintComponent() {
+  return (
+    <>
+      Human-readable hint to help LaTeX newbies. Supports <b>mark-up</b> for
+      e.g.{' '}
+      <a
+        target="_blank"
+        rel="noopener noreferrer"
+        href="https://www.overleaf.com/learn/latex/Errors/Extra_alignment_tab_has_been_changed_to_%5Ccr"
+      >
+        inline links
+      </a>
+      .
+    </>
+  )
+}
+
+export default {
+  title: 'PreviewLogEntry',
+  component: PreviewLogEntry,
+  args: {
+    file: 'foo/bar.tex',
+    line: 10,
+    column: 20,
+    message: 'Lorem ipsum',
+    content: `
+The LaTeX compiler output
+  * With a lot of details
+
+Wrapped in an HTML <pre> element with 
+      preformatted text which is to be presented exactly
+            as written in the HTML file
+
+                                              (whitespace included™)
+
+The text is typically rendered using a non-proportional ("monospace") font.
+
+LaTeX Font Info:    External font \`cmex10' loaded for size
+(Font)              <7> on input line 18.
+LaTeX Font Info:    External font \`cmex10' loaded for size
+(Font)              <5> on input line 18.
+! Undefined control sequence.
+<recently read> \\Zlpha
+
+ main.tex, line 23
+     
+`
+  }
+}

services/web/frontend/stories/use-expand-collapse.stories.js

@@ -0,0 +1,136 @@
+import React from 'react'
+import PropTypes from 'prop-types'
+import useExpandCollapse from '../js/shared/hooks/use-expand-collapse'
+
+function TestUI({ children, expandableProps, toggleProps }) {
+  return (
+    <>
+      <div {...expandableProps}>{children}</div>
+      <button {...toggleProps}>Expand/collapse</button>
+    </>
+  )
+}
+
+function VerticalTestUI(props) {
+  return <TestUI {...props}>{verticalContents}</TestUI>
+}
+
+function HorizontalTestUI(props) {
+  return <TestUI {...props}>{horizontalContents}</TestUI>
+}
+
+VerticalTestUI.propTypes = {
+  expandableProps: PropTypes.object,
+  toggleProps: PropTypes.object
+}
+
+HorizontalTestUI.propTypes = VerticalTestUI.propTypes
+
+TestUI.propTypes = {
+  ...VerticalTestUI.propTypes,
+  children: PropTypes.node
+}
+
+export const Vertical = args => {
+  const { expandableProps, toggleProps } = useExpandCollapse(args)
+  return (
+    <VerticalTestUI
+      expandableProps={expandableProps}
+      toggleProps={toggleProps}
+    />
+  )
+}
+
+export const VerticalInitiallyExpanded = args => {
+  const { expandableProps, toggleProps } = useExpandCollapse(args)
+  return (
+    <VerticalTestUI
+      expandableProps={expandableProps}
+      toggleProps={toggleProps}
+    />
+  )
+}
+VerticalInitiallyExpanded.args = {
+  initiallyExpanded: true
+}
+
+export const VerticalWithMinSize = args => {
+  const { expandableProps, toggleProps } = useExpandCollapse(args)
+  return (
+    <VerticalTestUI
+      expandableProps={expandableProps}
+      toggleProps={toggleProps}
+    />
+  )
+}
+VerticalWithMinSize.args = {
+  collapsedSize: 200
+}
+
+export const Horizontal = args => {
+  const { expandableProps, toggleProps } = useExpandCollapse(args)
+  return (
+    <HorizontalTestUI
+      expandableProps={expandableProps}
+      toggleProps={toggleProps}
+    />
+  )
+}
+Horizontal.args = {
+  dimension: 'width'
+}
+
+export const HorizontalInitiallyExpanded = args => {
+  const { expandableProps, toggleProps } = useExpandCollapse(args)
+  return (
+    <HorizontalTestUI
+      expandableProps={expandableProps}
+      toggleProps={toggleProps}
+    />
+  )
+}
+HorizontalInitiallyExpanded.args = {
+  initiallyExpanded: true
+}
+
+export const HorizontalWithMinSize = args => {
+  const { expandableProps, toggleProps } = useExpandCollapse(args)
+  return (
+    <HorizontalTestUI
+      expandableProps={expandableProps}
+      toggleProps={toggleProps}
+    />
+  )
+}
+HorizontalWithMinSize.args = {
+  dimension: 'width',
+  collapsedSize: 200
+}
+
+const defaultContentStyles = {
+  display: 'flex',
+  justifyContent: 'center',
+  alignItems: 'center',
+  fontSize: '2em',
+  backgroundImage: 'linear-gradient(to bottom, red, blue)',
+  width: '500px',
+  height: '500px',
+  color: '#FFF'
+}
+
+const verticalContents = <div style={defaultContentStyles}>Vertical</div>
+
+const horizontalContents = (
+  <div
+    style={{
+      ...defaultContentStyles,
+      backgroundImage: 'linear-gradient(to right, red, blue)'
+    }}
+  >
+    Horizontal
+  </div>
+)
+
+export default {
+  title: 'useExpandCollapse'
+}

services/web/frontend/stylesheets/_style_includes.less

@@ -55,6 +55,7 @@
 @import 'components/nvd3.less';
 @import 'components/nvd3_override.less';
 @import 'components/infinite-scroll.less';
+@import 'components/expand-collapse.less';
 
 // Components w/ JavaScript
 @import 'components/modals.less';

services/web/frontend/stylesheets/app/editor.less

@@ -14,6 +14,7 @@
 @import './editor/rich-text.less';
 @import './editor/publish-modal.less';
 @import './editor/outline.less';
+@import './editor/logs.less';
 
 @ui-layout-toggler-def-height: 50px;
 @ui-resizer-size: 7px;

services/web/frontend/stylesheets/app/editor/logs.less

@@ -0,0 +1,131 @@
+.logs-pane {
+  .full-size;
+  top: @pdf-top-offset;
+  padding: @padding-sm;
+  overflow-y: auto;
+  background-color: @logs-pane-bg;
+}
+
+.log-entry {
+  margin-bottom: @margin-sm;
+}
+
+.log-entry-header {
+  padding: 3px @padding-sm;
+  display: flex;
+  align-items: flex-start;
+  color: #fff;
+  border-radius: @border-radius-base @border-radius-base 0 0;
+  &:last-child {
+    border-radius: @border-radius-base;
+  }
+}
+
+.log-entry-header-error {
+  background-color: @ol-red;
+}
+
+.log-entry-header-warning {
+  background-color: @orange;
+}
+
+.log-entry-header-typesetting {
+  background-color: @ol-blue;
+}
+
+.log-entry-header-title,
+.log-entry-header-link {
+  font-family: @font-family-sans-serif;
+  font-size: @font-size-base;
+  line-height: @line-height-base;
+  font-weight: 700;
+  flex-grow: 1;
+  margin: 0;
+  color: #fff;
+}
+
+.log-entry-header-link {
+  border-width: 0;
+  flex-grow: 0;
+  text-align: right;
+  white-space: nowrap;
+  padding-left: @padding-sm;
+  &:hover,
+  &:focus {
+    outline: 0;
+    color: #fff;
+  }
+  &:focus {
+    text-decoration: none;
+  }
+}
+
+.log-entry-content {
+  background-color: #fff;
+  padding: @padding-sm;
+  &:last-child {
+    border-radius: 0 0 @border-radius-base @border-radius-base;
+  }
+}
+
+.log-entry-content-raw-expandable-container {
+  position: relative;
+  background-color: @ol-blue-gray-1;
+  border-radius: @border-radius-base;
+}
+
+.log-entry-content-raw-button-container-collapsed {
+  padding-bottom: 0;
+}
+
+.log-entry-content-raw {
+  font-size: @font-size-small;
+  color: @ol-blue-gray-4;
+  padding: @padding-sm @padding-sm @padding-xl @padding-sm;
+  margin: 0;
+}
+
+.log-entry-content-raw-collapsed {
+  padding-bottom: 0;
+}
+
+.log-entry-content-button-container {
+  position: absolute;
+  bottom: 0;
+  left: 0;
+  right: 0;
+  height: 40px;
+  padding-bottom: @padding-sm;
+  text-align: center;
+  border-radius: 0 0 @border-radius-base @border-radius-base;
+  &::before {
+    content: '';
+    position: absolute;
+    top: 0;
+    right: 0;
+    bottom: 0;
+    left: 0;
+    background-image: linear-gradient(0, @ol-blue-gray-1, transparent);
+    opacity: 0;
+    transition: opacity 0.15s ease-in-out;
+  }
+}
+
+.log-entry-content-button-container-collapsed::before {
+  opacity: 1;
+}
+
+.log-entry-btn-expand-collapse {
+  position: relative;
+  z-index: 1;
+  &:focus,
+  &:focus:active {
+    outline: 0;
+  }
+}
+
+.log-entry-human-readable-hint,
+.log-entry-human-readable-hint-link {
+  font-size: @font-size-small;
+  margin-top: @margin-sm;
+}

services/web/frontend/stylesheets/components/expand-collapse.less

@@ -0,0 +1,4 @@
+.expand-collapse-container {
+  overflow: hidden;
+  transition: height 0.15s ease-in-out, width 0.15s ease-in-out;
+}

services/web/frontend/stylesheets/core/ol-light-variables.less

@@ -89,6 +89,7 @@
 @editor-header-logo-background : url(/img/ol-brand/overleaf-o.svg) center / contain no-repeat;
 @project-name-color : @ol-blue-gray-3;
 @pdf-bg : @ol-blue-gray-0;
+@logs-pane-bg: @ol-blue-gray-1;
 
 // Navbar
 @navbar-default-bg : #FFF;

services/web/frontend/stylesheets/core/variables.less

@@ -1060,11 +1060,12 @@
 @chat-new-message-textarea-color: @ol-blue-gray-6;
 @chat-new-message-border-color: @editor-border-color;
 
-// PDF
+// PDF and logs
 @pdf-top-offset: @toolbar-small-height;
 @pdf-bg: @ol-blue-gray-1;
 @pdfjs-bg: transparent;
 @pdf-page-shadow-color: rgba(0, 0, 0, 0.5);
+@logs-pane-bg: @ol-blue-gray-5;
 @log-line-no-color: #fff;
 @log-hints-color: @ol-blue-gray-4;
 

services/web/locales/en.json

@@ -1,4 +1,6 @@
 {
+  "log_entry_description": "Log entry with level: \"__level__\"",
+  "navigate_log_source": "Navigate to log position in source code: __location__",
   "other_output_files": "Other output files",
   "toggle_output_files_list": "Toggle output files list",
   "n_warnings": "__count__ warning",

services/web/test/frontend/features/preview/components/preview-log-entry.test.js

@@ -0,0 +1,174 @@
+import React from 'react'
+import { expect } from 'chai'
+import sinon from 'sinon'
+import { screen, render, fireEvent } from '@testing-library/react'
+
+import PreviewLogEntry from '../../../../../frontend/js/features/preview/components/preview-log-entry.js'
+
+describe('<PreviewLogEntry />', function() {
+  const level = 'error'
+  const noOp = () => {}
+
+  describe('log entry description', function() {
+    for (const level of ['error', 'warning', 'typesetting']) {
+      it(`describes the log entry with ${level} information`, function() {
+        render(<PreviewLogEntry level={level} onLogEntryLinkClick={noOp} />)
+        screen.getByLabelText(`Log entry with level: "${level}"`)
+      })
+    }
+  })
+
+  describe('log location link', function() {
+    const file = 'foo.tex'
+    const line = 42
+    const column = 21
+    const onLogEntryLinkClick = sinon.stub()
+
+    afterEach(function() {
+      onLogEntryLinkClick.reset()
+    })
+
+    it('renders both file and line', function() {
+      render(
+        <PreviewLogEntry
+          file={file}
+          line={line}
+          level={level}
+          onLogEntryLinkClick={noOp}
+        />
+      )
+      screen.getByRole('button', {
+        name: `Navigate to log position in source code: ${file}, ${line}`
+      })
+    })
+
+    it('renders only file when line information is not available', function() {
+      render(
+        <PreviewLogEntry file={file} level={level} onLogEntryLinkClick={noOp} />
+      )
+      screen.getByRole('button', {
+        name: `Navigate to log position in source code: ${file}`
+      })
+    })
+
+    it('does not render when file information is not available', function() {
+      render(<PreviewLogEntry level={level} onLogEntryLinkClick={noOp} />)
+      expect(
+        screen.queryByRole('button', {
+          name: `Navigate to log position in source code: `
+        })
+      ).to.not.exist
+    })
+
+    it('calls the callback with file, line and column on click', function() {
+      render(
+        <PreviewLogEntry
+          file={file}
+          line={line}
+          column={column}
+          level={level}
+          onLogEntryLinkClick={onLogEntryLinkClick}
+        />
+      )
+      const linkToSourceButton = screen.getByRole('button', {
+        name: `Navigate to log position in source code: ${file}, ${line}`
+      })
+
+      fireEvent.click(linkToSourceButton)
+      expect(onLogEntryLinkClick).to.be.calledOnce
+      expect(onLogEntryLinkClick).to.be.calledWith({
+        file,
+        line: line,
+        column: column
+      })
+    })
+  })
+
+  describe('log entry contents', function() {
+    const logContent = 'foo bar latex error stuff baz'
+
+    it('renders collapsed contents by default', function() {
+      render(
+        <PreviewLogEntry
+          content={logContent}
+          level={level}
+          onLogEntryLinkClick={noOp}
+        />
+      )
+      screen.getByText(logContent)
+      screen.getByRole('button', {
+        name: 'Expand'
+      })
+    })
+
+    it('supports expanding contents', function() {
+      render(
+        <PreviewLogEntry
+          content={logContent}
+          level={level}
+          onLogEntryLinkClick={noOp}
+        />
+      )
+      screen.getByText(logContent)
+      const expandCollapseBtn = screen.getByRole('button', {
+        name: 'Expand'
+      })
+      fireEvent.click(expandCollapseBtn)
+      screen.getByRole('button', {
+        name: 'Collapse'
+      })
+    })
+
+    it('should not render at all when there are no log contents', function() {
+      const { container } = render(
+        <PreviewLogEntry level={level} onLogEntryLinkClick={noOp} />
+      )
+      expect(container.querySelector('.log-entry-content')).to.not.exist
+    })
+  })
+
+  describe('human-readable hints', function() {
+    const logContent = 'foo bar latex error stuff baz'
+    const logHintText = 'foo bar baz'
+    const logHint = <>{logHintText}</>
+    const infoURL = 'www.overleaf.com/learn/latex'
+
+    it('renders the hint', function() {
+      render(
+        <PreviewLogEntry
+          content={logContent}
+          humanReadableHintComponent={logHint}
+          extraInfoURL={infoURL}
+          level={level}
+          onLogEntryLinkClick={noOp}
+        />
+      )
+      screen.getByText(logHintText)
+    })
+
+    it('renders the link to learn more', function() {
+      render(
+        <PreviewLogEntry
+          content={logContent}
+          humanReadableHintComponent={logHint}
+          extraInfoURL={infoURL}
+          level={level}
+          onLogEntryLinkClick={noOp}
+        />
+      )
+      screen.getByRole('link', { name: 'Learn more' })
+    })
+
+    it('does not render the link when it is not available', function() {
+      render(
+        <PreviewLogEntry
+          content={logContent}
+          humanReadableHintComponent={logHint}
+          level={level}
+          onLogEntryLinkClick={noOp}
+        />
+      )
+      expect(screen.queryByRole('link', { name: 'Learn more' })).to.not.exist
+    })
+  })
+})

services/web/test/frontend/shared/hooks/use-expand-collapse.test.js

@@ -0,0 +1,122 @@
+import React from 'react'
+import PropTypes from 'prop-types'
+import { expect } from 'chai'
+import { render } from '@testing-library/react'
+
+import useExpandCollapse from '../../../../frontend/js/shared/hooks/use-expand-collapse'
+
+const sampleContent = (
+  <div>
+    <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
+    <p>Maecenas maximus ultrices sollicitudin.</p>
+    <p>Praesent mollis arcu eget molestie viverra.</p>
+    <p>Pellentesque eget molestie nisl, non hendrerit lectus.</p>
+  </div>
+)
+
+function ExpandCollapseTestUI({ expandCollapseArgs }) {
+  const { expandableProps } = useExpandCollapse(expandCollapseArgs)
+  return (
+    <>
+      <div {...expandableProps}>{sampleContent}</div>
+    </>
+  )
+}
+ExpandCollapseTestUI.propTypes = {
+  expandCollapseArgs: PropTypes.object
+}
+
+describe('useExpandCollapse', function() {
+  describe('custom CSS classes', function() {
+    it('supports a custom CSS class', function() {
+      const testArgs = {
+        classes: {
+          container: 'my-custom-class'
+        }
+      }
+      const { container } = render(
+        <ExpandCollapseTestUI expandCollapseArgs={testArgs} />
+      )
+      const elWithCustomCSSClass = container.querySelector('div')
+      expect(elWithCustomCSSClass).to.exist
+    })
+    it('supports an extra custom CSS class for the collapsed state', function() {
+      const testArgs = {
+        classes: {
+          containerCollapsed: 'my-custom-collapsed-class'
+        }
+      }
+
+      const { container } = render(
+        <ExpandCollapseTestUI expandCollapseArgs={testArgs} />
+      )
+      const elWithCustomCollapsedCSSClass = container.querySelector(
+        '.my-custom-collapsed-class'
+      )
+      expect(elWithCustomCollapsedCSSClass).to.exist
+    })
+    it('ignores the collapsed CSS class when expanded', function() {
+      const testArgs = {
+        initiallyExpanded: true,
+        classes: {
+          containerCollapsed: 'my-custom-collapsed-class'
+        }
+      }
+      const { container } = render(
+        <ExpandCollapseTestUI expandCollapseArgs={testArgs} />
+      )
+      const elWithCustomCollapsedCSSClass = container.querySelector(
+        '.my-custom-collapsed-class'
+      )
+      expect(elWithCustomCollapsedCSSClass).to.not.exist
+    })
+  })
+  describe('height and width support via dimension argument', function() {
+    it('defaults to height', function() {
+      const { container } = render(<ExpandCollapseTestUI />)
+      const expandCollapseEl = container.firstChild
+      expect(expandCollapseEl.style.height).to.not.be.empty
+      expect(expandCollapseEl.style.width).to.be.empty
+    })
+    it('supports width', function() {
+      const testArgs = {
+        dimension: 'width'
+      }
+      const { container } = render(
+        <ExpandCollapseTestUI expandCollapseArgs={testArgs} />
+      )
+      const expandCollapseEl = container.firstChild
+      expect(expandCollapseEl.style.height).to.be.empty
+      expect(expandCollapseEl.style.width).to.not.be.empty
+    })
+  })
+  describe('collapsed size support via collapsedSize argument', function() {
+    it('defaults to 0px', function() {
+      const { container } = render(<ExpandCollapseTestUI />)
+      const expandCollapseEl = container.firstChild
+      expect(expandCollapseEl.style.height).to.equal('0px')
+    })
+    it('supports a custom collapsed size', function() {
+      const testArgs = {
+        collapsedSize: 200
+      }
+      const { container } = render(
+        <ExpandCollapseTestUI expandCollapseArgs={testArgs} />
+      )
+      const expandCollapseEl = container.firstChild
+      expect(expandCollapseEl.style.height).to.equal('200px')
+    })
+    it('supports a custom collapsed size for width', function() {
+      const testArgs = {
+        collapsedSize: 200,
+        dimension: 'width'
+      }
+      const { container } = render(
+        <ExpandCollapseTestUI expandCollapseArgs={testArgs} />
+      )
+      const expandCollapseEl = container.firstChild
+      expect(expandCollapseEl.style.height).to.be.empty
+      expect(expandCollapseEl.style.width).to.equal('200px')
+    })
+  })
+})