```flex Bad theme={null} public class Greeter { public static var foo:Foo = new Foo(...); ... } ``` ```flex Fix theme={null} public class Greeter { public static const FOO:Foo = new Foo(...); ... } ```

Overriding Event.clone() is a required part of the API contract:

You are required to override the Event.clone() method in your Event subclass. The clone() method returns a cloned copy of the event object by setting the type property and any new properties in the clone. Typically, you define the clone() method to return an event instance created with the new operator.

```flex Bad theme={null} public class MyEvent extends Event {...} ``` ```flex Fix theme={null} public class MyEvent extends Event { ... override public function clone():Event { return new MyEvent(...); } ... } ```

Alert.show(...) can be useful for debugging during development, but in production mode this kind of pop-up could expose sensitive information to attackers, and should never be displayed.

```flex Bad theme={null} if (unexpectedCondition) { Alert.show("Unexpected Condition"); } ``` ```flex Fix theme={null} ```

Quoted from the Flex documentation :

When you define an Array variable in ActionScript, you specify Array as the data type of the variable. However, you cannot specify the data type of the elements of the Array.

To allow the Flex MXML compiler to perform type checking on Array elements, you can use the \[ArrayElementType] metadata tag to specify the allowed data type of the Array elements.

```flex Bad theme={null} public var newStringProperty:Array; public var newNumberProperty:Array; ``` ```flex Fix theme={null} [ArrayElementType("String")] public var newStringProperty:Array; [ArrayElementType("Number")] public var newNumberProperty:Array; ```

Any statement or block of statements can be identified by a label, but those labels should be used only on while, do-while and for statements. Using labels in any other context leads to unstructured, confusing code.

```flex Bad theme={null} myLabel:if (i % 2 == 0) { // Noncompliant if (i == 12) { print("12"); break myLabel; } print("Odd number, but not 12"); } ``` ```flex Fix theme={null} myLabel:for (i = 0; i < 10; i++) { // Compliant print("Loop"); break myLabel; } ```

In Flex, the semicolon is optional as a statement separator, but omitting semicolons can be confusing.

```flex Bad theme={null} function fun() { return // Noncompliant 5 // Noncompliant } print(fun()); // prints "undefined", not "5" ``` ```flex Fix theme={null} ```

The Security.exactSettings value should remain set at the default value of true. Setting this value to false could make the SWF vulnerable to cross-domain attacks.

```flex Bad theme={null} Security.exactSettings = false; ``` ```flex Fix theme={null} Security.exactSettings = true; ```

According to the ActionScript language reference, the star type:

Specifies that a property is untyped. Use of the asterisk symbol for a type annotation is equivalent to using no type annotation. Expressions that read from untyped properties are considered untyped expressions. Use of untyped expressions or properties is recommended in the following circumstances:

When you want to defer type checking to runtime. You can use an untyped property or expression to circumvent compile-time type checking in strict mode. Note, however, that runtime type checking of assignment statements occurs whether you use strict mode or not.

When you want to store the value undefined in a property. Unlike previous versions of ActionScript, the value undefined is not a member of the Object data type. You must use an untyped property to store the value undefined.

But deferring type checking to runtime can highly impact the robustness of the application because the compiler is unable to assist the developer.

```flex Bad theme={null} var obj:*; // Noncompliant var foo:* = new Something(); // Noncompliant ``` ```flex Fix theme={null} var obj:Something; var foo:Something = new Something(); ```

Because semicolons at the ends of statements are optional, starting function call arguments on a separate line makes the code confusing. It could lead to errors and most likely will lead to questions for maintainers.

What was the initial intent of the developer?

Define a function and then execute some unrelated code inside a closure ?
Pass the second function as a parameter to the first one ?

The first option will be the one chosen by the JavaScript interpreter.

By extension, and to improve readability, any kind of function call argument should not start on new line.

```flex Bad theme={null} var fn = function () { //... } (function () { // Noncompliant //... })(); ``` ```flex Fix theme={null} // define a function var fn = function () { //... }; // <-- semicolon added // then execute some code inside a closure (function () { //... })(); ```

Using plain string event names in even listeners is an anti-pattern; if the event is renamed, the application can start behaving unexpectedly. A constant variable should be used instead.

```flex Bad theme={null} import flash.display.Sprite; import flash.events.MouseEvent; class ChildSprite extends Sprite { public function ChildSprite() { ... addEventListener("CustomEvent", clickHandler); // Noncompliant } } function clickHandler(event:CustomEvent):void { trace("clickHandler detected an event of type: " + event.type); trace("the this keyword refers to: " + this); } ``` ```flex Fix theme={null} import flash.display.Sprite; import flash.events.MouseEvent; class ChildSprite extends Sprite { public const CUSTOM_EVENT:String = "CustomEvent"; public function ChildSprite() { ... addEventListener(CUSTOM_EVENT, clickHandler); } } function clickHandler(event:CustomEvent):void { trace("clickHandler detected an event of type: " + event.type); trace("the this keyword refers to: " + this); } ```

Access modifiers define which classes can access properties, variables, methods, and other classes. If an access modifier is not specified, the access level defaults to \`internal, which grants access to all classes in the same package. This may be what is intended, but it should be specified explicitly to avoid confusion.

Available access modifiers are:

internal - access allowed within the same package
private - access allowed only within the same class
protected - access allowed to the class and its child classes
public\` - unfettered access by all

```flex Bad theme={null} function checkResources():Boolean { ... return true; } ``` ```flex Fix theme={null} public function checkResources():Boolean { ... return true; } ```

The "ManagedEvents" metadata tag allows you to flag an event as being managed. By definition this "ManagedEvents" metadata tag should be used in pair with an "Event" metadata tag.

```flex Bad theme={null} [Event(name="message", type="my.package.MyEvemt")] [ManagedEvents("mes")] //This "mes" event is not defined with the "Event" metadata tag public class MyClass {...} ``` ```flex Fix theme={null} [Event(name="message", type="my.package.MyEvemt")] [ManagedEvents("message")] public class MyClass {...} ```

Never use with statements, since they decrease readability. When you do not specify a variable’s scope, you do not always know where you are setting properties, so your code can be confusing.

```flex Bad theme={null} with (foo) { // Noncompliant return x; // is it a property of foo or local variable ? } ``` ```flex Fix theme={null} return foo.x; ```

It can be expensive to instantiate a new object, and doing so inside a loop is typically an error. Instead, create the object once, before the loop.

```flex Bad theme={null} for (var i:int = 0; i < 10; i++) { var temp:MyObj = new MyObject(); // Noncompliant //... } ``` ```flex Fix theme={null} var temp:MyObj = new MyObject(); for (var i:int = 0; i < 10; i++) { //... } ```

The trace() function outputs debug statements, which can be read by anyone with a debug version of the Flash player. Because sensitive information could easily be exposed in this manner, trace() should never appear in production code.

```flex Bad theme={null} var val:Number = doCalculation(); trace("Calculation result: " + val); // Noncompliant ``` ```flex Fix theme={null} var val:Number = doCalculation(); ```

Declaring the package and class together has been deprecated since ActionScript 3. The package definition should be declared outside of the class definition even if the old syntax is still supported.

```flex Bad theme={null} class P.A {...} ``` ```flex Fix theme={null} package P { class A {...} } ```

Loggers should be:

\`private: not accessible outside of their parent classes. If another class needs to log something, it should instantiate its own logger.
static: not dependent on an instance of a class (an object). When logging something, contextual information can of course be provided in the messages but the logger should be created at class level to prevent creating a logger along with each object.
const\`: created once and only once per class.

```flex Bad theme={null} public const logger:ILogger = LogUtil.getLogger(MyClass); ``` ```flex Fix theme={null} private static const LOG:ILogger = LogUtil.getLogger(MyClass); ```

For example, with the default provided regular expression ^\[a-z]\[a-zA-Z0-9]\*\$, the function:

```flex Bad theme={null} function DoSomething(){...} /* Noncompliant */ ``` ```flex Fix theme={null} function doSomething(){...} ```

Using several "--" or "++" unary operators in the same arithmetic expression can quickly make the expression unreadable.

```flex Bad theme={null} var j:int = foo++ - --bar; ``` ```flex Fix theme={null} bar--; var j:int = foo++ - bar; ```

Nested control flow statements if, for, while, do while and switch are often key ingredients in creating what’s known as "Spaghetti code". This code smell can make your program difficult to understand and maintain.

When numerous control structures are placed inside one another, the code becomes a tangled, complex web. This significantly reduces the code’s readability and maintainability, and it also complicates the testing process.

```flex Bad theme={null} if (condition1) { // Compliant - depth = 1 /* ... */ if (condition2) { // Compliant - depth = 2 /* ... */ for(int i = 0; i < 10; i++) { // Compliant - depth = 3, not exceeding the limit /* ... */ if (condition4) { // Noncompliant - depth = 4 if (condition5) { // Depth = 5, exceeding the limit, but issues are only reported on depth = 4 /* ... */ } return; } } } } ``` ```flex Fix theme={null} ```

Overriding a method just to call the same method from the super class without performing any other actions is useless and misleading.

```flex Bad theme={null} override public function doSomething() : void { super.doSomething(); } override public function isLegal(action:Action) : Boolean { return super.isLegal(action); } ``` ```flex Fix theme={null} override public function doSomething() : void { super.doSomething(); // Compliant - not simply forwarding the call doSomethingElse(); } override public function isLegal(action:Action) : Boolean { return super.isLegal(new Action(...)); // Compliant - not simply forwarding the call } [Deprecated(replacement="isAuthorized")] override public function isLegal(action:Action) : Boolean { return super.isLegal(action); // Compliant as there is a metadata } ```

A listener can be attached to an object only after it has been constructed. So dispatching an event in a constructor is useless and error prone.

```flex Bad theme={null} public class MyClass { public function MyClass() { dispatchEvent( new Event( "uselessEvent" ) ); } } ``` ```flex Fix theme={null} ```

In ActionScript 3, constructor code is always interpreted rather than compiled by the JIT at runtime, which is why the body of a constructor should be as lightweight as possible. As soon as a constructor contains branches ("if", "for", "switch", …) an issue is logged.

```flex Bad theme={null} public class Foo { public function Foo() { if (condition) { // Noncompliant // ... } } } ``` ```flex Fix theme={null} public class Foo { public function Foo() { init() } private function init():void { if (condition) { // ... } } } ```

Usage of statements, operators and keywords specific to ActionScript 2 does not allow to migrate to ActionScript 3. This includes "intrinsic" keyword, set variable statement and following list of operators:

\`\<> (inequality) - use != instead
add (concatenation (strings)) - use + instead
eq (equality (strings)) - use == instead
ne (not equal (strings)) - use != instead
lt (less than (strings)) - use \< instead
le (less than or equal to (strings)) - use \<= instead
gt (greater than (strings)) - use > instead
ge (greater than or equal to (strings)) - use >= instead
and (logical and) - use && instead
or (logical or) - use || instead
not (logical not) - use !\` instead

```flex Bad theme={null} if (true != false) { // Compliant } if (true <> false) { // Noncompliant } set("varName", value); // Noncompliant varName = value; // Compliant ``` ```flex Fix theme={null} ```

Having multiple cases in a switch with the same condition is confusing at best. At worst, it’s a bug that is likely to induce further bugs as the code is maintained.

If the first case ends with a break, the second case will never be executed, rendering it dead code. Worse there is the risk in this situation that future maintenance will be done on the dead case, rather than on the one that’s actually used.

On the other hand, if the first case does not end with a break, both cases will be executed, but future maintainers may not notice that.

```flex Bad theme={null} switch(i) { case 1: //... break; case 5: //... break; case 3: //... break; case 1: // Noncompliant //... break; } ``` ```flex Fix theme={null} switch(i) { case 1: //... break; case 5: //... break; case 3: //... break; } ```

Creating a new variable with the type "Object" means that it may be used to store any kind of object. This feature may be required in some specific contexts, but it leaves the compiler unable to do any kind of type checking, and is therefore a hazardous practice.

```flex Bad theme={null} var obj:Object = new String(); // Noncompliant; Object used explicitly var foo = new Object(); // Noncompliant; Object used explicitly var bar = {name:String, age:int}; // Noncompliant; Object implicitly created ``` ```flex Fix theme={null} var obj:String = new String(); var foo:IPortfolio = new Portfolio(); class Person { public var name:String; public var age:int; } var bar:Person = new Person(); ```

A LocalConnection object is used to invoke a method in another LocalConnection object, either within a single SWF file or between multiple SWF files. This kind of local connection should be authorized only when the origin (domain) of the other Flex applications is perfectly defined.

```flex Bad theme={null} localConnection.allowDomain("*"); ``` ```flex Fix theme={null} localConnection.allowDomain("www.myDomain.com"); ```

According to the Flex documentation :

In an ActionScript file, when you define component events or other aspects of a component that affect more than a single property, you add the metadata tag outside the class definition so that the metadata is bound to the entire class, as the following example shows:

\`// Add the \[Event] metadata tag outside of the class file. \[Event(name="enableChange", type="flash.events.Event")] public class ModalText extends TextArea \{ ... // Define class properties/methods private var \_enableTA:Boolean; // Add the \[Inspectable] metadata tag before the individual property. \[Inspectable(defaultValue="false")] public function set enableTA(val:Boolean):void \{ \_enableTA = val; this.enabled = val; // Define event object, initialize it, then dispatch it. var eventObj:Event = new Event("enableChange"); dispatchEvent(eventObj); } }\`

In this example, the "enableChange" event must be considered part of the API. Therefore, it should be strongly typed.

```flex Bad theme={null} [Event(name="enableChange")] public class ModalText extends TextArea {...} ``` ```flex Fix theme={null} [Event(name="enableChange", type="flash.events.Event")] public class ModalText extends TextArea {...} ```

Even though this is syntactically correct, the void return type should not be used in the signature of a constructor. Indeed some developers might be confused by this syntax, believing that the constructor is in fact a standard function.

```flex Bad theme={null} public class Foo { public function Foo() : void {...} } ``` ```flex Fix theme={null} public class Foo { public function Foo() {...} } ```

The onEnterFrame event handler is continually invoked at the frame rate of the SWF file, regardless of which individual movie frame it is set for. Having too many onEnterFrame handlers can seriously degrade performance.

If the use of this event handler cannot be avoided entirely, then it should be created as close to its use as possible, and then destroyed as soon as possible afterward.

```flex Bad theme={null} movieClip.onEnterFrame = function () { // Noncompliant // ... } ``` ```flex Fix theme={null} ```

Making a public constant just const as opposed to static const leads to duplicating its value for every instance of the class, uselessly increasing the amount of memory required to execute the application.

```flex Bad theme={null} public class Myclass { public const THRESHOLD:int = 3; } ``` ```flex Fix theme={null} public class Myclass { public static const THRESHOLD:int = 3; } ```

A dynamic class defines an object that can be altered at run time by adding or changing properties and methods. This extremely powerful mechanism should be used very carefully, and only in very limited use cases.

Indeed, by definition dynamic classes make refactoring difficult and prevent the compiler from raising potential errors at compile time.

```flex Bad theme={null} dynamic public class DynamicFoo {...} ``` ```flex Fix theme={null} public class Foo //Note that the class has been renamed to avoid confusion {...} ```

Calling Security.allowDomain("\*") lets any domain cross-script into the domain of this SWF and exercise its functionality.

```flex Bad theme={null} Security.allowDomain("*"); ``` ```flex Fix theme={null} Security.allowDomain("www.myDomain.com"); ```

This is required by IEC 61508, under good programming style.

```flex Bad theme={null} function func1() { // Noncompliant - there are two points of exit if (false) { return; } } function func2() { // Noncompliant - there are two points of exit if (a > 0) { return 0; } return -1; } ``` ```flex Fix theme={null} function func1() { return; } function func2() { } function func3(); ```

Integer literals starting with a zero are octal rather than decimal values. While using octal values is fully supported, most developers do not have experience with them. They may not recognize octal values as such, mistaking them instead for decimal values.

```flex Bad theme={null} var myNumber:int = 010; // Noncompliant. myNumber will hold 8, not 10 - was this really expected? ``` ```flex Fix theme={null} var myNumber:int = 8; ```

Nested code - blocks of code inside blocks of code - is eventually necessary, but increases complexity. This is why keeping the code as flat as possible, by avoiding unnecessary nesting, is considered a good practice.

Merging if statements when possible will decrease the nesting of the code and improve its readability.

```flex Bad theme={null} if (condition1) { if (condition2) { // Noncompliant ... } } ``` ```flex Fix theme={null} if (condition1 && condition2) { ... } ```

An empty \{operationName} is generally considered bad practice and can lead to confusion, readability, and maintenance issues. Empty \{operationName}s bring no functionality and are misleading to others as they might think the \{operationName} implementation fulfills a specific and identified requirement.

There are several reasons for a \{operationName} not to have a body:

It is an unintentional omission, and should be fixed to prevent an unexpected behavior in production.
It is not yet, or never will be, supported. In this case an exception should be thrown.
The method is an intentionally-blank override. In this case a nested comment should explain the reason for the blank override.

```flex Bad theme={null} public function shouldNotBeEmpty():void { // Noncompliant - method is empty } public function notImplemented():void { // Noncompliant - method is empty } public override function emptyOnPurpose():void { // Noncompliant - method is empty } ``` ```flex Fix theme={null} public function shouldNotBeEmpty():void { doSomething(); } public function notImplemented():void { throw new Error("notImplemented() cannot be performed because ..."); } public override function emptyOnPurpose():void { // comment explaining why the method is empty } ```

If a private field is declared but not used locally, its limited visibility makes it dead code.

This is either a sign that some logic is missing or that the code should be cleaned.

Cleaning out dead code decreases the size of the maintained codebase, making it easier to understand and preventing bugs from being introduced.

```flex Bad theme={null} public class MyClass { private var foo:int = 4; // Noncompliant: foo is unused and should be removed public function compute(a:int):int{ return a * 4; } } ``` ```flex Fix theme={null} ```

A typical code smell known as unused function parameters refers to parameters declared in a function but not used anywhere within the function’s body. While this might seem harmless at first glance, it can lead to confusion and potential errors in your code. Disregarding the values passed to such parameters, the function’s behavior will be the same, but the programmer’s intention won’t be clearly expressed anymore. Therefore, removing function parameters that are not being utilized is considered best practice.

```flex Bad theme={null} override function doSomething(a:int):void { // ignored compute(a); } ... class AbstractSomething { public function doSomething(a:int) { // ignored throw new IllegalOperationError("doSomething() is abstract"); } ... interface I { function action(a:int, b:int); } class C extends I { function action(a:int, b:int) { // ignored return doSomethignWith(a); } } function clickHandler(event:MouseEvent):void { // ignored trace("click"); } ``` ```flex Fix theme={null} function doSomething(a:int, b:int):void // "b" is unused { compute(a); } ```

Shared naming conventions improve readability and allow teams to collaborate efficiently. This rule checks that all package names match a provided regular expression.

```flex Bad theme={null} package org.Example { // Noncompliant ... } ``` ```flex Fix theme={null} package org.example { ... } ```

Shared naming conventions allow teams to collaborate efficiently.

This rule raises an issue when a class name does not match a provided regular expression.

```flex Bad theme={null} public class myClass {...} /* Noncompliant */ ``` ```flex Fix theme={null} public class MyClass {...} ```

A \`for loop stop condition should test the loop counter against an invariant value (i.e. one that is true at both the beginning and ending of every loop iteration). Ideally, this means that the stop condition is set to a local variable just before the loop begins.

Stop conditions that are not invariant are slightly less efficient, as well as being difficult to understand and maintain, and likely lead to the introduction of errors in the future.

This rule tracks three types of non-invariant stop conditions:

When the loop counters are updated in the body of the for\` loop
When the stop condition depend upon a method call
When the stop condition depends on an object property, since such properties could change during the execution of the loop.

```flex Bad theme={null} for (var i = 0; i < 10; i++) { ... i = i - 1; // Noncompliant ... } for (var i = 0; i < getMaximumNumber(); i++) {...} ``` ```flex Fix theme={null} int stopCondition = getMaximumNumber(); for (var i = 0; i < stopCondition; i++) {...} ```

Having too many return statements in a function increases the function’s essential complexity because the flow of execution is broken each time a return statement is encountered. This makes it harder to read and understand the logic of the function.

```flex Bad theme={null} function myFunction():boolean { // Noncompliant as there are 4 return statements if (condition1) { return true; } else { if (condition2) { return false; } else { return true; } } return false; } ``` ```flex Fix theme={null} ```

The switch statement should be used only to clearly define some new branches in the control flow. As soon as a case clause contains too many statements this highly decreases the readability of the overall control flow statement. In such case, the content of the case clause should be extracted into a dedicated method.

```flex Bad theme={null} switch (myVariable) { case 0: // Noncompliant - 6 lines till next case or default case trace(""); trace(""); trace(""); trace(""); break; case 1: ... } ``` ```flex Fix theme={null} switch (myVariable) { case 0: printSomething() break; case 1: ... } ... private function printSomething() { trace(""); trace(""); trace(""); trace(""); } ```

Developers often use TODO tags to mark areas in the code where additional work or improvements are needed but are not implemented immediately. However, these TODO tags sometimes get overlooked or forgotten, leading to incomplete or unfinished code. This rule aims to identify and address unattended TODO tags to ensure a clean and maintainable codebase. This description explores why this is a problem and how it can be fixed to improve the overall code quality.

```flex Bad theme={null} void doSomething() { // TODO } ``` ```flex Fix theme={null} ```

A naming convention in software development is a set of guidelines for naming code elements like variables, functions, and classes.

The goal of a naming convention is to make the code more readable and understandable, which makes it easier to maintain and debug. It also ensures consistency in the code, especially when multiple developers are working on the same project.

This rule checks that field names match a provided regular expression.

```flex Bad theme={null} class MyClass { public var my_field:int; } ``` ```flex Fix theme={null} public class MyClass { public var myField:int; } ```

This rule raises an issue when a \{visibility} \{operationName} is never referenced in the code.

```flex Bad theme={null} public class Foo { public static function doSomething(): void // Compliant - public function { var foo:Foo = new Foo(); ... } private function unusedPrivateFunction(): void {...} // Noncompliant } ``` ```flex Fix theme={null} public class Foo { public static function doSomething(): void // Compliant - public function { var foo:Foo = new Foo(); ... } } ```

\`if statements with conditions that are always false have the effect of making blocks of code non-functional. if statements with conditions that are always true are completely redundant, and make the code less readable.

There are three possible causes for the presence of such code:

An if statement was changed during debugging and that debug code has been committed.
Some value was left unset.
Some logic is not doing what the programmer thought it did.

In any of these cases, unconditional if\` statements should be removed.

```flex Bad theme={null} if (true) { doSomething(); } ... if (false) { doSomethingElse(); } ``` ```flex Fix theme={null} ```

Empty statements represented by a semicolon ; are statements that do not perform any operation. They are often the result of a typo or a misunderstanding of the language syntax. It is a good practice to remove empty statements since they don’t add value and lead to confusion and errors.

```flex Bad theme={null} function doSomething():void { ; // Noncompliant - was used as a kind of TODO marker } function doSomethingElse():void { trace("Hello, world!");; // Noncompliant - double ; ... for (var i:int = 0; i < 3; trace(i), i++); // Noncompliant - Rarely, they are used on purpose as the body of a loop. It is a bad practice to have side-effects outside of the loop body ... } ``` ```flex Fix theme={null} function doSomething():void {} function doSomethingElse():void { trace("Hello, world!"); ... for (var i:int = 0; i < 3; i++){ trace(i); } ... } ```

The requirement for a final default clause is defensive programming. The clause should either take appropriate action, or contain a suitable comment as to why no action is taken.

```flex Bad theme={null} switch (param) { // Noncompliant - default clause is missing case 0: doSomething(); break; case 1: doSomethingElse(); break; } switch (param) { default: // Noncompliant - default clause should be the last one doSomething(); break; case 0: doSomethingElse(); break; } ``` ```flex Fix theme={null} switch (param) { case 0: doSomethingElse(); break; default: doSomethingElse(); break; } ```

Nested \`switch structures are difficult to understand because you can easily confuse the cases of an inner switch as belonging to an outer statement. Therefore nested switch statements should be avoided.

Specifically, you should structure your code to avoid the need for nested switch statements, but if you cannot, then consider moving the inner switch\` to another function.

```flex Bad theme={null} public function func(foo:Number, bar:Number):void { switch (foo) { case 1: // do something break; case 2: switch (bar) // Noncompliant { case 89: // It's easy to lose sight of what's being tested; is it foo or bar? // ... break; case 90: // ... break; } break; case 3: // do something break; default: break; } } ``` ```flex Fix theme={null} public function func(foo:Number, bar:Number):void { switch (foo) { case 1: // ... break; case 2: handleBar(bar); break; case 3: // ... break; default: break; } } public function handleBar(bar:Number):void { switch (bar) { case 89: // ... break; case 90: // ... break; } } ```

An unused local variable is a variable that has been declared but is not used anywhere in the block of code where it is defined. It is dead code, contributing to unnecessary complexity and leading to confusion when reading the code. Therefore, it should be removed from your code to maintain clarity and efficiency.

```flex Bad theme={null} public function numberOfMinutes(hours:int):int { var seconds:int = 0; // Noncompliant - seconds is unused return hours * 60; } ``` ```flex Fix theme={null} public function numberOfMinutes(hours:int):int { return hours * 60; } ```

A naming convention in software development is a set of guidelines for naming code elements like variables, functions, and classes. \{identifier\_capital\_plural} hold the meaning of the written code. Their names should be meaningful and follow a consistent and easily recognizable pattern. Adhering to a consistent naming convention helps to make the code more readable and understandable, which makes it easier to maintain and debug. It also ensures consistency in the code, especially when multiple developers are working on the same project.

This rule checks that \{identifier} names match a provided regular expression.

```flex Bad theme={null} public function doSomething(my_param:int):void { var LOCAL:int; ... } ``` ```flex Fix theme={null} public function doSomething(myParam):void { var local; ... } ```

Undocumented APIs pose significant challenges in software development for several reasons:

Lack of Clarity: developers struggling to understand how to use the API correctly. This can lead to misuse and unexpected results.
Increased Development Time: developers spending extra time reading and understanding the source code, which slows down the development process.
Error Prone: developers are more likely to make mistakes that lead to bugs or system crashes when the intent or the error handling of an API is not clear.
Difficult Maintenance and Updates: developers may not understand the existing functionality well enough to add new features without breaking the existing ones.
Poor Collaboration: collaboration, when there is lack of documentation, leads to confusion and inconsistencies.

```flex Bad theme={null} /** * @private // This class and all its elements are ignored */ public class MyClass { // Compliant public var myLabel:String; // Compliant } public class AnotherClass { // Noncompliant; class not @private and not documented /** * @private */ public var name:String; // Compliant } ``` ```flex Fix theme={null} public class MyClass { public var myLabel:String; public function myMethod(param1:String):Boolean { // ... } } ```

Local variables should not shadow class fields

```flex Bad theme={null} class Foo { public var myField:int; public function doSomething():String { var myField:int = 0; // Noncompliant //... } } ``` ```flex Fix theme={null} ```