[MM-59059] Re enable markdown preview for channel header in user advanced settings (#27440)

webapp/channels/src/components/edit_channel_header_modal/__snapshots__/edit_channel_header_modal.test.tsx.snap

@@ -84,7 +84,6 @@ exports[`components/EditChannelHeaderModal edit direct message channel 1`] = `
         <TextboxLinks
           hasExceededCharacterLimit={false}
           hasText={true}
-          isMarkdownPreviewEnabled={false}
           previewMessageLink={
             <Memo(MemoizedFormattedMessage)
               defaultMessage="Edit"
@@ -215,7 +214,6 @@ exports[`components/EditChannelHeaderModal error with intl message 1`] = `
         <TextboxLinks
           hasExceededCharacterLimit={false}
           hasText={true}
-          isMarkdownPreviewEnabled={false}
           previewMessageLink={
             <Memo(MemoizedFormattedMessage)
               defaultMessage="Edit"
@@ -364,7 +362,6 @@ exports[`components/EditChannelHeaderModal error without intl message 1`] = `
         <TextboxLinks
           hasExceededCharacterLimit={false}
           hasText={true}
-          isMarkdownPreviewEnabled={false}
           previewMessageLink={
             <Memo(MemoizedFormattedMessage)
               defaultMessage="Edit"
@@ -505,7 +502,6 @@ exports[`components/EditChannelHeaderModal should match snapshot, init 1`] = `
         <TextboxLinks
           hasExceededCharacterLimit={false}
           hasText={true}
-          isMarkdownPreviewEnabled={false}
           previewMessageLink={
             <Memo(MemoizedFormattedMessage)
               defaultMessage="Edit"
@@ -636,7 +632,6 @@ exports[`components/EditChannelHeaderModal submitted 1`] = `
         <TextboxLinks
           hasExceededCharacterLimit={false}
           hasText={true}
-          isMarkdownPreviewEnabled={false}
           previewMessageLink={
             <Memo(MemoizedFormattedMessage)
               defaultMessage="Edit"

webapp/channels/src/components/edit_channel_header_modal/edit_channel_header_modal.tsx

@@ -253,7 +253,6 @@ export class EditChannelHeaderModal extends React.PureComponent<Props, State> {
                         </div>
                         <div className='post-create-footer'>
                             <TextboxLinks
-                                isMarkdownPreviewEnabled={this.props.markdownPreviewFeatureIsEnabled}
                                 showPreview={this.props.shouldShowPreview}
                                 updatePreview={this.setShowPreview}
                                 hasText={this.state.header ? this.state.header.length > 0 : false}

webapp/channels/src/components/edit_channel_header_modal/index.ts

@@ -13,16 +13,12 @@ import {getBool} from 'mattermost-redux/selectors/entities/preferences';
 import {setShowPreviewOnEditChannelHeaderModal} from 'actions/views/textbox';
 import {showPreviewOnEditChannelHeaderModal} from 'selectors/views/textbox';
 
-import {Constants} from 'utils/constants';
-import {isFeatureEnabled} from 'utils/utils';
-
 import type {GlobalState} from 'types/store';
 
 import EditChannelHeaderModal from './edit_channel_header_modal';
 
 function mapStateToProps(state: GlobalState) {
     return {
-        markdownPreviewFeatureIsEnabled: isFeatureEnabled(Constants.PRE_RELEASE_FEATURES.MARKDOWN_PREVIEW, state),
         shouldShowPreview: showPreviewOnEditChannelHeaderModal(state),
         ctrlSend: getBool(state, Preferences.CATEGORY_ADVANCED_SETTINGS, 'send_on_ctrl_enter'),
     };

webapp/channels/src/components/textbox/textbox_links.tsx

@@ -12,7 +12,6 @@ type Props = {
     previewMessageLink?: ReactNode;
     hasText?: boolean;
     hasExceededCharacterLimit?: boolean;
-    isMarkdownPreviewEnabled: boolean;
     updatePreview?: (showPreview: boolean) => void;
 };
 
@@ -21,7 +20,6 @@ function TextboxLinks({
     previewMessageLink,
     hasText = false,
     hasExceededCharacterLimit = false,
-    isMarkdownPreviewEnabled,
     updatePreview,
 }: Props) {
     const togglePreview = (e: MouseEvent) => {
@@ -48,9 +46,7 @@ function TextboxLinks({
         );
     }
 
-    let previewLink = null;
+    const previewLink = (
-    if (isMarkdownPreviewEnabled) {
-        previewLink = (
         <button
             id='previewLink'
             onClick={togglePreview}
@@ -66,7 +62,6 @@ function TextboxLinks({
             )}
         </button>
     );
-    }
 
     const helpText = (
         <div

webapp/channels/src/components/user_settings/advanced/user_settings_advanced.tsx

@@ -28,7 +28,8 @@ import PerformanceDebuggingSection from './performance_debugging_section';
 import SettingDesktopHeader from '../headers/setting_desktop_header';
 import SettingMobileHeader from '../headers/setting_mobile_header';
 
-const PreReleaseFeatures = Constants.PRE_RELEASE_FEATURES;
+type PreReleaseFeaturesType = Record<string, {label: string; description: string}>;
+const PreReleaseFeatures: PreReleaseFeaturesType = Constants.PRE_RELEASE_FEATURES;
 
 type Settings = {
     [key: string]: string | undefined;
@@ -63,7 +64,7 @@ export type Props = {
 };
 
 type State = {
-    preReleaseFeatures: typeof PreReleaseFeatures;
+    preReleaseFeatures: PreReleaseFeaturesType;
     settings: Settings;
     enabledFeatures: number;
     isSaving: boolean;
@@ -92,7 +93,6 @@ export default class AdvancedSettingsDisplay extends React.PureComponent<Props,
         };
 
         const PreReleaseFeaturesLocal = JSON.parse(JSON.stringify(PreReleaseFeatures));
-        delete PreReleaseFeaturesLocal.MARKDOWN_PREVIEW;
         const preReleaseFeaturesKeys = Object.keys(PreReleaseFeaturesLocal);
 
         let enabledFeatures = 0;
@@ -709,7 +709,7 @@ export default class AdvancedSettingsDisplay extends React.PureComponent<Props,
             const inputs = [];
 
             this.state.preReleaseFeaturesKeys.forEach((key) => {
-                const feature = this.state.preReleaseFeatures[key as keyof typeof PreReleaseFeatures];
+                const feature = this.state.preReleaseFeatures[key as keyof PreReleaseFeaturesType];
                 inputs.push(
                     <div key={'advancedPreviewFeatures_' + feature.label}>
                         <div className='checkbox'>

webapp/channels/src/utils/constants.tsx

@@ -1971,12 +1971,7 @@ export const Constants = {
         COMMAND_SUGGESTION_USER: 'user',
     },
     FeatureTogglePrefix: 'feature_enabled_',
-    PRE_RELEASE_FEATURES: {
+    PRE_RELEASE_FEATURES: {},
-        MARKDOWN_PREVIEW: {
-            label: 'markdown_preview', // github issue: https://github.com/mattermost/platform/pull/1389
-            description: 'Show markdown preview option in message input box',
-        },
-    },
     OVERLAY_TIME_DELAY_SMALL: 100,
     OVERLAY_TIME_DELAY: 400,
     OVERLAY_DEFAULT_TRIGGER: ['hover', 'focus'],