[eslint] Enforce optional chaining

This simplify the code that we write

Bug: 397260638
Change-Id: I9757acd0d700af2675264c7f4d2c22fa89b7dc8f
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6287365
Commit-Queue: Mathias Bynens <[email protected]>
Reviewed-by: Mathias Bynens <[email protected]>
Auto-Submit: Nikolay Vitkov <[email protected]>

Author: Lightning00Blade

eslint.config.mjs

@@ -531,6 +531,8 @@ export default [
         },
       ],
 
+      '@typescript-eslint/prefer-optional-chain': 'error',
+
       'rulesdir/no-underscored-properties': 'error',
       'rulesdir/inline-type-imports': 'error',
 

extensions/cxx_debugging/e2e/TestDriver.ts

@@ -115,9 +115,9 @@ describe('CXX Debugging Extension Test Suite', function() {
 
               if (variableName.startsWith('$')) {
                 if (variableType) {
-                  assert.isTrue(scopeVariable && scopeVariable.endsWith(`: ${variableType}`));
+                  assert.isTrue(scopeVariable?.endsWith(`: ${variableType}`));
                 } else if (value) {
-                  assert.isTrue(scopeVariable && scopeVariable.endsWith(`: ${value}`));
+                  assert.isTrue(scopeVariable?.endsWith(`: ${value}`));
                 }
               } else {
                 if (variableType) {

extensions/cxx_debugging/src/DevToolsPluginHost.ts

@@ -109,7 +109,7 @@ export interface Storage {
 
 export declare const chrome: Chrome.DevTools.Chrome&{storage?: Storage};
 
-if (typeof chrome !== 'undefined' && typeof chrome.storage !== 'undefined') {
+if (typeof chrome?.storage !== 'undefined') {
   const {storage} = chrome;
   const {languageServices} = chrome.devtools;
 

extensions/cxx_debugging/src/MEMFSResourceLoader.ts

@@ -26,7 +26,7 @@ export class ResourceLoader implements DWARFSymbols.ResourceLoader {
         // get a 404 response.
         console.error(symbolsDwpError);
       }
-      if (!(symbolsDwpResponse && symbolsDwpResponse.ok)) {
+      if (!(symbolsDwpResponse?.ok)) {
         // Often this won't exist, but remember the missing file because if
         // we can't find symbol information later it is likely because this
         // file was missing.
@@ -37,7 +37,7 @@ export class ResourceLoader implements DWARFSymbols.ResourceLoader {
       }
       const [symbolsData, symbolsDwpData] = await Promise.all([
         symbolsResponse.arrayBuffer(),
-        symbolsDwpResponse && symbolsDwpResponse.ok ? symbolsDwpResponse.arrayBuffer() : undefined,
+        symbolsDwpResponse?.ok ? symbolsDwpResponse.arrayBuffer() : undefined,
       ]);
       void hostInterface.reportResourceLoad(url.href, {success: true, size: symbolsData.byteLength});
       if (symbolsDwpData) {

front_end/core/common/Object.ts

@@ -85,7 +85,7 @@ export class ObjectWrapper<Events> implements EventTarget<Events> {
   }
 
   hasEventListeners(eventType: keyof Events): boolean {
-    return Boolean(this.listeners && this.listeners.has(eventType));
+    return Boolean(this.listeners?.has(eventType));
   }
 
   dispatchEventToListeners<T extends keyof Events>(

front_end/core/common/ParsedURL.ts

@@ -372,7 +372,7 @@ export class ParsedURL {
 
     // Return absolute URLs with normalized path and other components as-is.
     const parsedHref = this.fromString(trimmedHref);
-    if (parsedHref && parsedHref.scheme) {
+    if (parsedHref?.scheme) {
       const securityOrigin = parsedHref.securityOrigin();
       const pathText = normalizePath(parsedHref.path);
       const queryText = parsedHref.queryParams && `?${parsedHref.queryParams}`;

front_end/core/common/Settings.ts

@@ -838,10 +838,10 @@ export class VersionController {
         continue;
       }
       // Zero out saved percentage sizes, and they will be restored to defaults.
-      if (value.vertical && value.vertical.size && value.vertical.size < 1) {
+      if (value.vertical?.size && value.vertical.size < 1) {
         value.vertical.size = 0;
       }
-      if (value.horizontal && value.horizontal.size && value.horizontal.size < 1) {
+      if (value.horizontal?.size && value.horizontal.size < 1) {
         value.horizontal.size = 0;
       }
       setting.set(value);

front_end/core/dom_extension/DOMExtension.ts

@@ -341,7 +341,7 @@ Node.prototype.traversePreviousNode = function(stayWithin?: Node): Node|null {
     return null;
   }
   let node: ChildNode|(ChildNode | null) = this.previousSibling;
-  while (node && node.lastChild) {
+  while (node?.lastChild) {
     node = node.lastChild;
   }
   if (node) {

front_end/core/i18n/i18nImpl.ts

@@ -48,7 +48,7 @@ export function getAllSupportedDevToolsLocales(): string[] {
  */
 function getLocaleFetchUrl(locale: Intl.UnicodeBCP47LocaleIdentifier, location: string): string {
   const remoteBase = Root.Runtime.getRemoteBase(location);
-  if (remoteBase && remoteBase.version && !BUNDLED_LOCALES.has(locale)) {
+  if (remoteBase?.version && !BUNDLED_LOCALES.has(locale)) {
     return REMOTE_FETCH_PATTERN.replace('@HOST@', 'devtools://devtools')
         .replace('@VERSION@', remoteBase.version)
         .replace('@LOCALE@', locale);

front_end/core/platform/DOMUtilities.ts

@@ -9,7 +9,7 @@
  */
 export function deepActiveElement(doc: Document): Element|null {
   let activeElement: Element|null = doc.activeElement;
-  while (activeElement && activeElement.shadowRoot && activeElement.shadowRoot.activeElement) {
+  while (activeElement?.shadowRoot?.activeElement) {
     activeElement = activeElement.shadowRoot.activeElement;
   }
   return activeElement;