Dart Code Snippets to help you write basic control loop faster.

Dart Code Snippets



The body of the while loop is executed repeatedly as long as the condition specified at the top of the loop remains true.

while



The for loop code inside of the curly braces iterates through the count array, zero by zero, counting up from 0.



The loop iterates over the items variable.

for in



The code block says if the variable "case" is an integer, then the program should break and if it is not, it should continue.

switch case



This code creates a block that will only be executed if the condition specified in the if statement is true.



The if () block will only be executed if the code between the curly braces is true. If it's not true, the else block will be executed.

if else



The "try" block will execute until it either succeeds or fails, and then the "catch" block will execute. If the "try" block fails, the "catch" block will execute and then the program will jump to the "finally" block.



The code in question is a function definition. It starts with the keyword void, followed by the function name, main. The parentheses tell the compiler that the main function takes an argument, which in this case are the strings "List<String>.

main

Angular snippets for TypeScript

angular



The ModelService class is simply extending the EntityCollectionServiceBase class. This class provides a generic interface for all our models, and it is up to the user to provide their own implementations of the get() method. We also inject the service ElementsFactory into the constructor so that we can get hold of the underlying collection of models.

NgRx Data Entity Collection Data Service



The trackBy function uses the id property of the name model to find the corresponding track.

TrackBy Function



What does EntityDataModule.forRoot() do?

This block of code creates an instance of the EntityDataModule class and sets the entityConfig property to the instance of the EntityConfiguration class that was passed as an input parameter.

NgRx Data Import Entity Data Module



This is importing the @ngrx/data library, then creating an entityMetadataMap of the model 1 in the entityConfig . This entityMetadataMap contains an entity for the model 1.

NgRx Data Entity Metadata



A selector is a type of codeconstructor used for specifying a particular pattern of code execution. In this case, the selector is used to create a function that will be called when the select event is triggered. The selector takes three arguments: select, which is a function that will be called when the select event is triggered; state, which is a state object that is passed to the selectLogic function; and props, which is a list of property values that will be passed to the selectLogic function.

NgRx Create Selector w/ Props



export const selectFeatureProperty = createSelector(
select: (state: State) => state.

NgRx Create Selector



EffectName$ is a variable that will hold the name of the new effect. This effect will be created by calling createEffect(). The effects that are available in React are listed here.

The first parameter is a function that will be called every time an action is fired from the parent component. This function will receive two arguments: the action object and the current state of the children. The this.actions argument is an object that contains all of the action instances that are children of the component.

The second parameter is ofType(). This function will return a React Component type. This type will be used to determine how the function will be called. The function that is passed in as the second argument will be called every time an action is fired.

The third parameter is operator(). This function will be called every time an action is fired and the type of the action is not ofType(). This function will receive three arguments: the action object, the current state of the children, and an error object. The third parameter is an object that can be used to store information about the action. The key value pairs in this object will be relevant for the specific action that was fired.

The fourth and last parameter is apiSource. This function will

NgRx Create Effect for API Call



This code creates an effect that returns an observable stream that will emit completion whenever the actions stream is finished.

NgRx Create Effect



This code is creating a reducer function. The reducer function takes two arguments, state and action. state is the current state of the reducer, and action is the action that was dispatched. The reducer function then returns a new reducer, which will take the current state and the action as input and return a new state.

NgRx Create Reducer



The code exports a function called action with the given name. In this case, the action function takes an object literal with the type key set to "Event".

NgRx Create Action w/ Props



The following code exports an action called "createAction". This action will be used to create a new event.

NgRx Create Action



Here, the code imports the StoreModule, the EffectsModule, and the StoreDevtoolsModule. The store module is then exported. The environment variable is an array of modules that the application should load. The production environment loads the StoreDevtoolsModule.

NgRx Store Module



The code in this example imports the Injectable module from the Angular Core library. Next, the code imports the Resolve and ActivatedRouteSnapshot modules from the Angular Router library. Finally, the YourResolver class is exported and it implements the Resolve interface.

In the resolve method, the code defines a resolve function that takes an ActivatedRouteSnapshot as an input. The resolve function returns an Observable object that will either emit an object representing the result of the route resolution or a Promise object that will be resolved when the route is resolved. The return type of the resolve function is an ObjectToResolve type.

When the resolve function is called, the route parameter will be a ActivatedRouteSnapshot object. The route snapshot object will contain information about the route that was resolved. The information that is contained in the route snapshot object will vary depending on the router implementation that is used.

In this example, the code uses the type hinting feature to declare the return type of the resolve function as ObjectToResolve. This will allow the resolve function to be used with any type of object that can be converted to an ObjectToResolve type.

Angular Resolver


The map operator is used to transform a function into another function. In this case, it is used to create a function that takes an input of type Observable and returns an output of type Map.

RxJs Operator Import


Observable is an RxJS library that allows us to subscribe to data changes and implement observable operators on top of that.

An observable is an object that represents a source of data that can be subscribed to and "observed." When an observable is subscribed to, it will send notifications as soon as its data changes. The operator functions are then responsible for taking that data and doing something with it.

For our example, we'll be using the observable to track the number of items in our list. The code starts by importing the Observable library and creating an observable instance. The next line creates a subscription to the observable and passes in our list of items as an input. Next, we use the subscribe() operator to subscribe to the data changes occurring on the observable. Finally, we use the handleData() operator to actually get the data from the observable and display it on the screen.

RxJs Import



The code creates a constructor that takes one argument, @Optional(). If the argument is not null, then the parentModule property is set to the argument. If the argument is null, then the parentModule property is set to the empty string. The constructor then prints a message telling the user that ModuleName has already been loaded.

Angular Module SkipSelf Constructor



checkEvents iterates through the events object and when an event is found that matches the eventName property, it breaks out of the loop, returning true.

Angular Router Events



This file contains a NetworkAwarePreloadStrategy class that implements the PreloadingStrategy interface.

This class has a preload() method that returns an Observable object. This object will be filled with data if the user has a good connection. The preload() method checks to see if the user has a save data connection by checking the value of the navigator.connection property. If the user has a save data connection, the preload() method will avoid preloading any routes that have the Slow-2g, 2g, 3g, or 4g effectiveType values in the avoidTheseConnections array. If the user does not have a save data connection, the preload() method will preload all routes.

The hasGoodConnection() method checks to see if the user has a good connection by querying the value of the navigator.connection property. If the user has a good connection, the hasGoodConnection() method will return true . Otherwise, the hasGoodConnection() method will return false .

Angular Network Aware Preload Strategy


The code first imports the PreloadingStrategy and Route classes from the @angular/router package. Next, it imports the Observable and of functions from the rxjs package. Finally, it defines a PreloadSelectedModulesList class which implements the PreloadingStrategy interface.

The PreloadSelectedModulesList class defines the preload() method. This method takes a route object and a load function as arguments. The preload() method will return an Observable object if the route object has data associated with it, or an Object type if the route object does not have data associated with it. The load() function will be called if the preload() method returns an Observable object. The load() function will be called with the route object as the only argument.

The preload() method will return an Observable object if the route object has data associated with it, or an Object type if the route object does not have data associated with it. The load() function will be called if the preload() method returns an Observable object. The load() function will be called with the route object as the only argument.

Angular Opt In Preload Strategy



@Injectable({providedIn: 'root'})
export class ComponentNameComponent implements CanDeactivate<ComponentNameComponent> {
 canDeactivate(
   component: ComponentNameComponent,
   currentRoute: ActivatedRouteSnapshot, 
   currentState: RouterStateSnapshot
  ): Observable<boolean> {
    return this.props.canDeactivate;
  }
}


In this code, the @Injectable() decorator is used to declare that the NameGuard and CanDeactivate classes are injectable. The @Injectable() decorator also declares that the NameGuard and CanDeactivate classes will be able to access the canDeactivate property of the ComponentNameComponent class. The canDeactivate property is a property of the ComponentNameComponent class that returns an Observable object, a Promise object, or a boolean value. The code also declares that the NameGuard and CanDeactivate classes will be able to access the currentRoute, currentState, and canDeactivate properties of the ActivatedRouteSnapshot and RouterStateSnapshot classes. The canDeactivate property of the ActivatedRouteSnapshot and RouterStateSnapshot classes is

Angular CanDeactivate Guard



This code imports the Injectable class from the Angular core library and also brings in the Route and CanLoad services. The NameGuard class implements the CanLoad interface, which means that it can check to see if a route can be loaded before trying to do anything else. In this case, the canLoad() method returns true, so the route will be loaded.

Angular CanLoad Guard

Angular CanActivateChild Guard



The @Injectable() decorator allows us to inject the NameGuard class into our application. The constructor of the NameGuard class sets up the canActivate method which returns true if the user can activate the route.

Angular CanActivate Guard


This code imports the NameComponent into the module.

Angular Module



The @Directive annotation is used to indicate that the class contains a directive. The selector is used to identify the directive.

Angular Directive



In the code, the import statement imports the Routes module. The Routes object is an array of strings. Each string is a route name.

The routes array contains two routes: "home" and "about".

Route definitions


In this code, the NgModule is first imported. Next, the BrowserModule and HttpModule are imported. Finally, the AppComponent is declared and bootstrapped.

Angular Root Module


In the above code, we are importing the Component from @angular/core. We are also specifying that our AppComponent class will be exported. This means that outside of our AppComponent class, we can reference the RouterOutlet.

Angular Root Component


The code is saying that when the code runs, it will call a function that will have the name "service.function" and it will subscribe to it so that it will be called every time the function is called. Within the service.function, it will call the this.property = arg function, which will set the this.property variable to the value that was passed into the service.function.

Subscribe



This code creates an instance of the EventEmitter class, and assigns it to the eventName variable. The eventName variable will be used to store the details of the event that is being created.

Output Event



The @Injectable() decorator registers the YourInterceptor class as a HTTP interceptor. The intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> function takes a req object and returns an Observable that emits HttpEvent objects. The handle(req: HttpRequest<any>) function of the next object receives a req object and calls the handle() method of the HttpHandler object that was passed as an argument.

Angular HttpInterceptor Empty



The HeaderInterceptor helps intercept HTTP requests and responses. It initializes an HttpRequest with the headers of the request and a clone of the headers. It returns an Observable that is emitted when the handle method is called on the next HttpHandler .

The handle method takes an HttpHandler as a parameter. The handler is executed when the Observable is emitted by the HeaderInterceptor . The handler can access the req object, which contains the HttpRequest that was intercepted. The authReq object is a copy of the headers of the request that was intercepted.

Angular HttpInterceptor for Headers



To intercept a request, we need to provide the interceptor with a handler and a next. The handler will be invoked for every request that passes through the interceptor and the next provides the hook into the routing system.

We then pipe the incoming request into our tap function, which takes an Observable as its input and returns an Observable that emits events of the same type as the input Observable. In our case, that's HttpEvents.

The tap function will keep track of the current time and if the event that it's receiving is an HttpEvent of type HttpResponse, it will also print out the elapsed time for the request.

Angular HttpInterceptor for Logging



The @Injectable decorator tells Angular that this class should be injected with the HttpClient service.

Angular HttpClient Service


This line subscribes to a particular parameter. Every time a new parameter is received, the line will call the tap() method, passing the parameter's value as the parameter's ID.

Routing Params Subscribe



The get() method of the HttpClient class returns the requested web resource.

HttpClient get

Angular Lazy Route Path



This code tells the React component to use the NameComponent component.

Angular Eager Route Path



The code uses the ** template string to represent the path parameter. The PathNotFoundComponent is used to display an error message if the requested path is not found.

Angular 404 Route Path



The code creates an array of objects, containing the path and the component of the childpath. The childpath element has the path and the component of the childcomponent as children.

Angular Route Path with Children



The pathMatch property refers to a regular expression that can be used to determine if a path is a complete path or not. If the pathMatch property is set to full, then the path property will only contain the path portion of the URL. If the pathMatch property is set to partial, then the path property will contain the path, file name, and extension, if any, of the URL. If the pathMatch property is set to none, then the path property will contain the full URL.

Angular Default Route Path



In the above code, the @Injectable annotation indicates that the ServiceNameService class can be injected into other classes. This class exports an interface, which means that other classes can consume it and implement the necessary methods to work with the ServiceNameService class.

Name	Language	Author	Uses
while	Dart	l lucycodes42	0
for	Dart	l lucycodes42	3
for in	Dart	l lucycodes42	3
switch case	Dart	l lucycodes42	2
if	Dart	l lucycodes42	14
if else	Dart	l lucycodes42	1
try	Dart	l lucycodes42	8
main	Dart	l lucycodes42	15
NgRx Data Entity Collection Data Service	TypeScript	l lucycodes42	0
TrackBy Function	TypeScript	l lucycodes42	0
NgRx Data Import Entity Data Module	TypeScript	l lucycodes42	0
NgRx Data Entity Metadata	TypeScript	l lucycodes42	0
NgRx Create Selector w/ Props	TypeScript	l lucycodes42	0
NgRx Create Selector	TypeScript	l lucycodes42	0
NgRx Create Effect for API Call	TypeScript	l lucycodes42	3
NgRx Create Effect	TypeScript	l lucycodes42	0
NgRx Create Reducer	TypeScript	l lucycodes42	0
NgRx Create Action w/ Props	TypeScript	l lucycodes42	0
NgRx Create Action	TypeScript	l lucycodes42	0
NgRx Store Module	TypeScript	l lucycodes42	0
Angular Resolver	TypeScript	l lucycodes42	0
RxJs Operator Import	TypeScript	l lucycodes42	0
RxJs Import	TypeScript	l lucycodes42	1
Angular Module SkipSelf Constructor	TypeScript	l lucycodes42	1
Angular Router Events	TypeScript	l lucycodes42	0
Angular Network Aware Preload Strategy	TypeScript	l lucycodes42	1
Angular Opt In Preload Strategy	TypeScript	l lucycodes42	0
Angular CanDeactivate Guard	TypeScript	l lucycodes42	0
Angular CanLoad Guard	TypeScript	l lucycodes42	0
Angular CanActivateChild Guard	TypeScript	l lucycodes42	0
Angular CanActivate Guard	TypeScript	l lucycodes42	0
Angular Module	TypeScript	l lucycodes42	0
Angular Directive	TypeScript	l lucycodes42	0
Route definitions	TypeScript	l lucycodes42	0
Angular Root Module	TypeScript	l lucycodes42	0
Angular Root Component	TypeScript	l lucycodes42	0
Subscribe	TypeScript	l lucycodes42	0
Output Event	TypeScript	l lucycodes42	0
Angular HttpInterceptor Empty	TypeScript	l lucycodes42	0
Angular HttpInterceptor for Headers	TypeScript	l lucycodes42	0
Angular HttpInterceptor for Logging	TypeScript	l lucycodes42	0
Angular HttpClient Service	TypeScript	l lucycodes42	0
Routing Params Subscribe	TypeScript	l lucycodes42	0
HttpClient get	TypeScript	l lucycodes42	0
Angular Lazy Route Path	TypeScript	l lucycodes42	0
Angular Eager Route Path	TypeScript	l lucycodes42	0
Angular 404 Route Path	TypeScript	l lucycodes42	0
Angular Route Path with Children	TypeScript	l lucycodes42	0
Angular Default Route Path	TypeScript	l lucycodes42	0
Angular Service	TypeScript	l lucycodes42	0

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