Null chaining for [] and ()

ampproject · May 13, 2021 · dcf39a5 · dcf39a5
1 parent 9540be7
commit dcf39a5
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Showing 5 changed files with 12 additions and 22 deletions.
diff --git a/src/core/data-structures/finite-state-machine.js b/src/core/data-structures/finite-state-machine.js
@@ -65,11 +65,7 @@ export class FiniteStateMachine {
     this.state_ = newState;
 
     const transition = this.statesToTransition_(oldState, newState);
-    const callback = this.transitions_[transition];
-
-    if (callback) {
-      callback();
-    }
+    this.transitions_[transition]?.();
   }
 
   /**

diff --git a/src/core/data-structures/promise.js b/src/core/data-structures/promise.js
@@ -99,8 +99,8 @@ export class LastAddedResolver {
     this.count_ = 0;
 
     if (opt_promises) {
-      for (let i = 0; i < opt_promises.length; i++) {
-        this.add(opt_promises[i]);
+      for (const promise of opt_promises) {
+        this.add(promise);
       }
     }
   }

diff --git a/src/core/data-structures/signals.js b/src/core/data-structures/signals.js
@@ -66,7 +66,7 @@ export class Signals {
    * @return {!Promise<!TimestampDef>}
    */
   whenSignal(name) {
-    let promiseStruct = this.promiseMap_ && this.promiseMap_[name];
+    let promiseStruct = this.promiseMap_?.[name];
     if (!promiseStruct) {
       const result = this.map_[name];
       if (result != null) {
@@ -101,9 +101,9 @@ export class Signals {
       // Do not duplicate signals.
       return;
     }
-    const time = opt_time == undefined ? Date.now() : opt_time;
+    const time = opt_time ?? Date.now();
     this.map_[name] = time;
-    const promiseStruct = this.promiseMap_ && this.promiseMap_[name];
+    const promiseStruct = this.promiseMap_?.[name];
     if (promiseStruct?.resolve) {
       promiseStruct.resolve(time);
       promiseStruct.resolve = undefined;
@@ -123,7 +123,7 @@ export class Signals {
       return;
     }
     this.map_[name] = error;
-    const promiseStruct = this.promiseMap_ && this.promiseMap_[name];
+    const promiseStruct = this.promiseMap_?.[name];
     if (promiseStruct?.reject) {
       promiseStruct.reject(error);
       promiseStruct.promise.catch(() => {});
@@ -141,7 +141,7 @@ export class Signals {
       delete this.map_[name];
     }
     // Reset promise it has already been resolved.
-    const promiseStruct = this.promiseMap_ && this.promiseMap_[name];
+    const promiseStruct = this.promiseMap_?.[name];
     if (promiseStruct && !promiseStruct.resolve) {
       delete this.promiseMap_[name];
     }

diff --git a/src/core/error.js b/src/core/error.js
@@ -21,7 +21,7 @@
  */
 export function duplicateErrorIfNecessary(error) {
   const messageProperty = Object.getOwnPropertyDescriptor(error, 'message');
-  if (messageProperty && messageProperty.writable) {
+  if (messageProperty?.writable) {
     return error;
   }
 
@@ -44,8 +44,7 @@ export function duplicateErrorIfNecessary(error) {
 export function createErrorVargs(var_args) {
   let error = null;
   let message = '';
-  for (let i = 0; i < arguments.length; i++) {
-    const arg = arguments[i];
+  for (const arg of arguments) {
     if (arg instanceof Error && !error) {
       error = duplicateErrorIfNecessary(arg);
     } else {
@@ -74,10 +73,7 @@ export function rethrowAsync(var_args) {
   setTimeout(() => {
     // __AMP_REPORT_ERROR is installed globally per window in the entry point.
     // It may not exist for Bento components without the runtime.
-    if (self.__AMP_REPORT_ERROR) {
-      self.__AMP_REPORT_ERROR(error);
-    }
-
+    self.__AMP_REPORT_ERROR?.(error);
     throw error;
   });
 }

diff --git a/src/core/types/object/json.js b/src/core/types/object/json.js
@@ -81,9 +81,7 @@ export function tryParseJson(json, opt_onFailed) {
   try {
     return parseJson(json);
   } catch (e) {
-    if (opt_onFailed) {
-      opt_onFailed(e);
-    }
+    opt_onFailed.?(e);
     return null;
   }
 }