Added option to hide line numbers

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

src/components/views/messages/TextualBody.js

@@ -81,6 +81,7 @@ export default class TextualBody extends React.Component {
     }
 
     _applyFormatting() {
+        const showLineNumbers = SettingsStore.getValue("showCodeLineNumbers");
         this.activateSpoilers([this._content.current]);
 
         // pillifyLinks BEFORE linkifyElement because plain room/user URLs in the composer
@@ -101,10 +102,11 @@ export default class TextualBody extends React.Component {
                     this._handleCodeBlockExpansion(pres[i]);
                     this._addCodeExpansionButton(div, pres[i]);
                     this._addCodeCopyButton(div);
-                    // TODO: Add option to disable this
+                    if (showLineNumbers) {
                         this._addLineNumbers(pres[i]);
                     }
                 }
+            }
             // Highlight code
             const codes = ReactDOM.findDOMNode(this).getElementsByTagName("code");
             if (codes.length >0) {

src/components/views/settings/tabs/user/PreferencesUserSettingsTab.js

@@ -47,6 +47,7 @@ export default class PreferencesUserSettingsTab extends React.Component {
         'showRedactions',
         'enableSyntaxHighlightLanguageDetection',
         'expandCodeByDefault',
+        'showCodeLineNumbers',
         'showJoinLeaves',
         'showAvatarChanges',
         'showDisplaynameChanges',

src/settings/Settings.ts

@@ -305,6 +305,11 @@ export const SETTINGS: {[setting: string]: ISetting} = {
         displayName: _td('Expand code blocks by default'),
         default: false,
     },
+    "showCodeLineNumbers": {
+        supportedLevels: LEVELS_ACCOUNT_SETTINGS,
+        displayName: _td('Show line numbers in code blocks'),
+        default: true,
+    },
     "Pill.shouldShowPillAvatar": {
         supportedLevels: LEVELS_ACCOUNT_SETTINGS,
         displayName: _td('Show avatars in user and room mentions'),