{ "id": "guide/ajs-quick-reference", "title": "AngularJS to Angular concepts: Quick reference", "contents": "\n\n\n
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AngularJS to Angular concepts: Quick referencelink

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Angular is the name for the Angular of today and tomorrow.\nAngularJS is the name for all v1.x versions of Angular.

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This guide helps you transition from AngularJS to Angular\nby mapping AngularJS syntax to the equivalent Angular syntax.

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See the Angular syntax in this .

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Template basicslink

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Templates are the user-facing part of an Angular application and are written in HTML.\nThe following table lists some of the key AngularJS template features with their equivalent Angular template syntax.

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\n AngularJS\n \n Angular\n
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Bindings/interpolationlink

\n \n Your favorite hero is: {{vm.favoriteHero}}\n \n

In AngularJS, an expression in curly braces denotes one-way binding.\nThis binds the value of the element to a property in the controller\nassociated with this template.

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When using the controller as syntax,\nthe binding is prefixed with the controller alias (vm or $ctrl) because you\nhave to be specific about the source of the binding.

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Bindings/interpolationlink

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\nYour favorite hero is: {{favoriteHero}}\n\n

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In Angular, a template expression in curly braces still denotes one-way binding.\nThis binds the value of the element to a property of the component.\nThe context of the binding is implied and is always the\nassociated component, so it needs no reference variable.

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For more information, see the Interpolation guide.

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Filterslink

\n \n <td>{{movie.title | uppercase}}</td>\n \n

To filter output in AngularJS templates, use the pipe character (|) and one or more filters.

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This example filters the title property to uppercase.

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Pipeslink

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\n<td>{{movie.title | uppercase}}</td>\n\n

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In Angular you use similar syntax with the pipe (|) character to filter output, but now you call them pipes.\nMany (but not all) of the built-in filters from AngularJS are\nbuilt-in pipes in Angular.

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For more information, see Filters/pipes below.

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Local variableslink

\n \n <tr ng-repeat=\"movie in vm.movies\">\n <td>{{movie.title}}</td>\n </tr>\n \n

Here, movie is a user-defined local variable.

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Input variableslink

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\n<tr *ngFor=\"let movie of movies\">\n <td>{{movie.title}}</td>\n</tr>\n\n

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Angular has true template input variables that are explicitly defined using the let keyword.

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For more information, see the Structural directive shorthand section of Structural Directives.

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Template directiveslink

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AngularJS provides more than seventy built-in directives for templates.\nMany of them aren't needed in Angular because of its more capable and expressive binding system.\nThe following are some of the key AngularJS built-in directives and their equivalents in Angular.

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\n AngularJS\n \n Angular\n
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ng-applink

\n \n <body ng-app=\"movieHunter\">\n \n

The application startup process is called bootstrapping.

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Although you can bootstrap an AngularJS app in code,\nmany applications bootstrap declaratively with the ng-app directive,\ngiving it the name of the application's module (movieHunter).

\n 		\n

Bootstrappinglink

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\nimport { enableProdMode } from '@angular/core';\nimport { platformBrowserDynamic } from '@angular/platform-browser-dynamic';\n\nimport { AppModule } from './app/app.module';\nimport { environment } from './environments/environment';\n\nif (environment.production) {\n enableProdMode();\n}\n\nplatformBrowserDynamic().bootstrapModule(AppModule);\n\n\n\n

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\nimport { NgModule } from '@angular/core';\nimport { BrowserModule } from '@angular/platform-browser';\n\nimport { AppComponent } from './app.component';\n\n@NgModule({\n imports: [ BrowserModule ],\n declarations: [ AppComponent ],\n bootstrap: [ AppComponent ]\n})\nexport class AppModule { }\n\n\n

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Angular doesn't have a bootstrap directive.\nTo launch the app in code, explicitly bootstrap the application's root module (AppModule)\nin main.ts\nand the application's root component (AppComponent) in app.module.ts.

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ng-classlink

\n \n <div ng-class=\"{active: isActive}\">\n <div ng-class=\"{active: isActive,\n shazam: isImportant}\">\n \n

In AngularJS, the ng-class directive includes/excludes CSS classes\nbased on an expression. That expression is often a key-value control object with each\nkey of the object defined as a CSS class name, and each value defined as a template expression\nthat evaluates to a Boolean value.

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In the first example, the active class is applied to the element if isActive is true.

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You can specify multiple classes, as shown in the second example.

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ngClasslink

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\n<div [ngClass]=\"{'active': isActive}\">\n<div [ngClass]=\"{'active': isActive,\n 'shazam': isImportant}\">\n<div [class.active]=\"isActive\">\n\n

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In Angular, the ngClass directive works similarly.\nIt includes/excludes CSS classes based on an expression.

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In the first example, the active class is applied to the element if isActive is true.

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You can specify multiple classes, as shown in the second example.

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Angular also has class binding, which is a good way to add or remove a single class,\nas shown in the third example.

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For more information see Attribute, class, and style bindings page.

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ng-clicklink

\n \n <button ng-click=\"vm.toggleImage()\">\n <button ng-click=\"vm.toggleImage($event)\">\n \n

In AngularJS, the ng-click directive allows you to specify custom behavior when an element is clicked.

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In the first example, when the user clicks the button, the toggleImage() method in the controller referenced by the vm controller as alias is executed.

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The second example demonstrates passing in the $event object, which provides details about the event\nto the controller.

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Bind to the click eventlink

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\n<button (click)=\"toggleImage()\">\n<button (click)=\"toggleImage($event)\">\n\n

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AngularJS event-based directives do not exist in Angular.\nRather, define one-way binding from the template view to the component using event binding.

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For event binding, define the name of the target event within parenthesis and\nspecify a template statement, in quotes, to the right of the equals. Angular then\nsets up an event handler for the target event. When the event is raised, the handler\nexecutes the template statement.

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In the first example, when a user clicks the button, the toggleImage() method in the associated component is executed.

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The second example demonstrates passing in the $event object, which provides details about the event\nto the component.

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For a list of DOM events, see: https://developer.mozilla.org/en-US/docs/Web/Events.

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For more information, see the Event binding page.

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ng-controllerlink

\n \n <div ng-controller=\"MovieListCtrl as vm\">\n \n

In AngularJS, the ng-controller directive attaches a controller to the view.\nUsing the ng-controller (or defining the controller as part of the routing) ties the\nview to the controller code associated with that view.

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Component decoratorlink

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\n@Component({\n selector: 'app-movie-list',\n templateUrl: './movie-list.component.html',\n styleUrls: [ './movie-list.component.css' ],\n})\n\n

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In Angular, the template no longer specifies its associated controller.\nRather, the component specifies its associated template as part of the component class decorator.

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For more information, see Architecture Overview.

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ng-hidelink

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In AngularJS, the ng-hide directive shows or hides the associated HTML element based on\nan expression. For more information, see ng-show.

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Bind to the hidden propertylink

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In Angular, you use property binding; there is no built-in hide directive.\nFor more information, see ng-show.

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ng-hreflink

\n \n <a ng-href=\"{{ angularDocsUrl }}\">Angular Docs</a>\n \n

The ng-href directive allows AngularJS to preprocess the href property so that it\ncan replace the binding expression with the appropriate URL before the browser\nfetches from that URL.

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In AngularJS, the ng-href is often used to activate a route as part of navigation.

\n \n <a ng-href=\"#{{ moviesHash }}\">Movies</a>\n \n

Routing is handled differently in Angular.

\n 		\n

Bind to the href propertylink

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\n<a [href]=\"angularDocsUrl\">Angular Docs</a>\n\n

\n

Angular uses property binding; there is no built-in href directive.\nPlace the element's href property in square brackets and set it to a quoted template expression.

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For more information see the Property binding page.

\n

In Angular, href is no longer used for routing. Routing uses routerLink, as shown in the following example.

\n

\n<a [routerLink]=\"['/movies']\">Movies</a>\n\n

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For more information on routing, see Defining a basic route\nin the Routing & Navigation page.

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ng-iflink

\n \n <table ng-if=\"movies.length\">\n \n

In AngularJS, the ng-if directive removes or recreates a portion of the DOM,\nbased on an expression. If the expression is false, the element is removed from the DOM.

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In this example, the <table> element is removed from the DOM unless the movies array has a length greater than zero.

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*ngIflink

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\n<table *ngIf=\"movies.length\">\n\n

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The *ngIf directive in Angular works the same as the ng-if directive in AngularJS. It removes\nor recreates a portion of the DOM based on an expression.

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In this example, the <table> element is removed from the DOM unless the movies array has a length.

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The (*) before ngIf is required in this example.\nFor more information, see Structural Directives.

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ng-modellink

\n \n <input ng-model=\"vm.favoriteHero\"/>\n \n

In AngularJS, the ng-model directive binds a form control to a property in the controller associated with the template.\nThis provides two-way binding, whereby any change made to the value in the view is synchronized with the model, and any change to the model is synchronized with the value in the view.

\n 		\n

ngModellink

\n

\n<input [(ngModel)]=\"favoriteHero\" />\n\n

\n

In Angular, two-way binding is denoted by [()], descriptively referred to as a \"banana in a box\". This syntax is a shortcut for defining both property binding (from the component to the view)\nand event binding (from the view to the component), thereby providing two-way binding.

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For more information on two-way binding with ngModel, see the NgModel—Two-way binding to\nform elements with [(ngModel)]\nsection of the Built-in directives page.

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ng-repeatlink

\n \n <tr ng-repeat=\"movie in vm.movies\">\n \n

In AngularJS, the ng-repeat directive repeats the associated DOM element\nfor each item in the specified collection.

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In this example, the table row (<tr>) element repeats for each movie object in the collection of movies.

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*ngForlink

\n

\n<tr *ngFor=\"let movie of movies\">\n\n

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The *ngFor directive in Angular is similar to the ng-repeat directive in AngularJS. It repeats\nthe associated DOM element for each item in the specified collection.\nMore accurately, it turns the defined element (<tr> in this example) and its contents into a template and\nuses that template to instantiate a view for each item in the list.

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Notice the other syntax differences:\nThe (*) before ngFor is required;\nthe let keyword identifies movie as an input variable;\nthe list preposition is of, not in.

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For more information, see Structural Directives.

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ng-showlink

\n \n <h3 ng-show=\"vm.favoriteHero\">\n Your favorite hero is: {{vm.favoriteHero}}\n </h3>\n \n

In AngularJS, the ng-show directive shows or hides the associated DOM element, based on\nan expression.

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In this example, the <div> element is shown if the favoriteHero variable is truthy.

\n 		\n

Bind to the hidden propertylink

\n

\n<h3 [hidden]=\"!favoriteHero\">\n Your favorite hero is: {{favoriteHero}}\n</h3>\n\n

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Angular uses property binding; there is no built-in show directive.\nFor hiding and showing elements, bind to the HTML hidden property.

\n

To conditionally display an element, place the element's hidden property in square brackets and\nset it to a quoted template expression that evaluates to the opposite of show.

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In this example, the <div> element is hidden if the favoriteHero variable is not truthy.

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For more information on property binding, see the Property binding page.

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ng-srclink

\n \n <img ng-src=\"{{movie.imageurl}}\">\n \n

The ng-src directive allows AngularJS to preprocess the src property so that it\ncan replace the binding expression with the appropriate URL before the browser\nfetches from that URL.

\n 		\n

Bind to the src propertylink

\n

\n<img [src]=\"movie.imageurl\">\n\n

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Angular uses property binding; there is no built-in src directive.\nPlace the src property in square brackets and set it to a quoted template expression.

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For more information on property binding, see the Property binding page.

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ng-stylelink

\n \n <div ng-style=\"{color: colorPreference}\">\n \n

In AngularJS, the ng-style directive sets a CSS style on an HTML element\nbased on an expression. That expression is often a key-value control object with each\nkey of the object defined as a CSS property, and each value defined as an expression\nthat evaluates to a value appropriate for the style.

\n

In the example, the color style is set to the current value of the colorPreference variable.

\n 		\n

ngStylelink

\n

\n<div [ngStyle]=\"{'color': colorPreference}\">\n<div [style.color]=\"colorPreference\">\n\n

\n

In Angular, the ngStyle directive works similarly. It sets a CSS style on an HTML element based on an expression.

\n

In the first example, the color style is set to the current value of the colorPreference variable.

\n

Angular also has style binding, which is good way to set a single style. This is shown in the second example.

\n

For more information on style binding, see the Style binding section of the\nAttribute binding page.

\n

For more information on the ngStyle directive, see the NgStyle\nsection of the Built-in directives page.

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ng-switchlink

\n \n <div ng-switch=\"vm.favoriteHero &&\n vm.checkMovieHero(vm.favoriteHero)\">\n <div ng-switch-when=\"true\">\n Excellent choice!\n </div>\n <div ng-switch-when=\"false\">\n No movie, sorry!\n </div>\n <div ng-switch-default>\n Please enter your favorite hero.\n </div>\n </div>\n \n

In AngularJS, the ng-switch directive swaps the contents of\nan element by selecting one of the templates based on the current value of an expression.

\n

In this example, if favoriteHero is not set, the template displays \"Please enter ...\".\nIf favoriteHero is set, it checks the movie hero by calling a controller method.\nIf that method returns true, the template displays \"Excellent choice!\".\nIf that methods returns false, the template displays \"No movie, sorry!\".

\n 		\n

ngSwitchlink

\n

\n<span [ngSwitch]=\"favoriteHero &&\n checkMovieHero(favoriteHero)\">\n <p *ngSwitchCase=\"true\">\n Excellent choice!\n </p>\n <p *ngSwitchCase=\"false\">\n No movie, sorry!\n </p>\n <p *ngSwitchDefault>\n Please enter your favorite hero.\n </p>\n</span>\n\n

\n

In Angular, the ngSwitch directive works similarly.\nIt displays an element whose *ngSwitchCase matches the current ngSwitch expression value.

\n

In this example, if favoriteHero is not set, the ngSwitch value is null\nand *ngSwitchDefault displays, \"Please enter ...\".\nIf favoriteHero is set, the app checks the movie hero by calling a component method.\nIf that method returns true, the app selects *ngSwitchCase=\"true\" and displays: \"Excellent choice!\"\nIf that methods returns false, the app selects *ngSwitchCase=\"false\" and displays: \"No movie, sorry!\"

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The (*) before ngSwitchCase and ngSwitchDefault is required in this example.

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For more information, see The NgSwitch directives\nsection of the Built-in directives page.

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Filters/pipeslink

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Angular pipes provide formatting and transformation for data in the template, similar to AngularJS filters.\nMany of the built-in filters in AngularJS have corresponding pipes in Angular.\nFor more information on pipes, see Pipes.

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\n AngularJS\n \n Angular\n
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currencylink

\n \n <td>{{movie.price | currency}}</td>\n \n

Formats a number as currency.

\n 		\n

currencylink

\n

\n<td>{{movie.price | currency:'USD':true}}</td>\n\n

\n

The Angular currency pipe is similar although some of the parameters have changed.

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datelink

\n \n <td>{{movie.releaseDate | date}}</td>\n \n

Formats a date to a string based on the requested format.

\n 		\n

datelink

\n

\n<td>{{movie.releaseDate | date}}</td>\n\n

\n

The Angular date pipe is similar.

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\n

filterlink

\n \n <tr ng-repeat=\"movie in movieList | filter: {title:listFilter}\">\n \n

Selects a subset of items from the defined collection, based on the filter criteria.

\n 		\n

nonelink

\n

For performance reasons, no comparable pipe exists in Angular. Do all your filtering in the component. If you need the same filtering code in several templates, consider building a custom pipe.

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\n

jsonlink

\n \n <pre>{{movie | json}}</pre>\n \n

Converts a JavaScript object into a JSON string. This is useful for debugging.

\n 		\n

jsonlink

\n

\n<pre>{{movie | json}}</pre>\n\n

\n

The Angular json pipe does the same thing.

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limitTolink

\n \n <tr ng-repeat=\"movie in movieList | limitTo:2:0\">\n \n

Selects up to the first parameter (2) number of items from the collection\nstarting (optionally) at the beginning index (0).

\n 		\n

slicelink

\n

\n<tr *ngFor=\"let movie of movies | slice:0:2\">\n\n

\n

The SlicePipe does the same thing but the order of the parameters is reversed, in keeping\nwith the JavaScript Slice method.\nThe first parameter is the starting index; the second is the limit.\nAs in AngularJS, coding this operation within the component instead could improve performance.

\n
\n

lowercaselink

\n \n <td>{{movie.title | lowercase}}</td>\n \n

Converts the string to lowercase.

\n 		\n

lowercaselink

\n

\n<td>{{movie.title | lowercase}}</td>\n\n

\n

The Angular lowercase pipe does the same thing.

\n
\n

numberlink

\n \n <td>{{movie.starRating | number}}</td>\n \n

Formats a number as text.

\n 		\n

numberlink

\n

\n<td>{{movie.starRating | number}}</td>\n<td>{{movie.starRating | number:'1.1-2'}}</td>\n<td>{{movie.approvalRating | percent: '1.0-2'}}</td>\n\n

\n

The Angular number pipe is similar.\nIt provides more functionality when defining\nthe decimal places, as shown in the second example above.

\n

Angular also has a percent pipe, which formats a number as a local percentage\nas shown in the third example.

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orderBylink

\n \n <tr ng-repeat=\"movie in movieList | orderBy : 'title'\">\n \n

Displays the collection in the order specified by the expression.\nIn this example, the movie title orders the movieList.

\n 		\n

nonelink

\n

For performance reasons, no comparable pipe exists in Angular.\nInstead, use component code to order or sort results. If you need the same ordering or sorting code in several templates, consider building a custom pipe.

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Modules/controllers/componentslink

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In both AngularJS and Angular, modules help you organize your application into cohesive blocks of functionality.

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In AngularJS, you write the code that provides the model and the methods for the view in a controller.\nIn Angular, you build a component.

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Because much AngularJS code is in JavaScript, JavaScript code is shown in the AngularJS column.\nThe Angular code is shown using TypeScript.

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\n AngularJS\n \n Angular\n
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IIFElink

\n \n (function () {\n ...\n }());\n \n

In AngularJS, an immediately invoked function expression (or IIFE) around controller code\nkeeps it out of the global namespace.

\n 		\n

nonelink

\n

This is a nonissue in Angular because ES 2015 modules\nhandle the namespacing for you.

\n

For more information on modules, see the Modules section of the\nArchitecture Overview.

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Angular moduleslink

\n \n angular.module(\"movieHunter\", [\"ngRoute\"]);\n \n

In AngularJS, an Angular module keeps track of controllers, services, and other code.\nThe second argument defines the list of other modules that this module depends upon.

\n 		\n

NgModuleslink

\n

\nimport { NgModule } from '@angular/core';\nimport { BrowserModule } from '@angular/platform-browser';\n\nimport { AppComponent } from './app.component';\n\n@NgModule({\n imports: [ BrowserModule ],\n declarations: [ AppComponent ],\n bootstrap: [ AppComponent ]\n})\nexport class AppModule { }\n\n\n

\n

NgModules, defined with the NgModule decorator, serve the same purpose:

\n

imports: specifies the list of other modules that this module depends upon\n declaration: keeps track of your components, pipes, and directives.

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For more information on modules, see NgModules.

\n
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Controller registrationlink

\n \n angular\n .module(\"movieHunter\")\n .controller(\"MovieListCtrl\",\n [\"movieService\",\n MovieListCtrl]);\n \n

AngularJS has code in each controller that looks up an appropriate Angular module\nand registers the controller with that module.

\n

The first argument is the controller name. The second argument defines the string names of\nall dependencies injected into this controller, and a reference to the controller function.

\n 		\n

Component decoratorlink

\n

\n@Component({\n selector: 'app-movie-list',\n templateUrl: './movie-list.component.html',\n styleUrls: [ './movie-list.component.css' ],\n})\n\n

\n

Angular adds a decorator to the component class to provide any required metadata.\nThe @Component decorator declares that the class is a component and provides metadata about\nthat component such as its selector (or tag) and its template.

\n

This is how you associate a template with logic, which is defined in the component class.

\n

For more information, see the Components\nsection of the Architecture Overview page.

\n
\n

Controller functionlink

\n \n function MovieListCtrl(movieService) {\n }\n \n

In AngularJS, you write the code for the model and methods in a controller function.

\n 		\n

Component classlink

\n

\nexport class MovieListComponent {\n}\n\n

\n

In Angular, you create a component class to contain the data model and control methods. Use the TypeScript export keyword to export the class so that the functionality can be imported into NgModules.

\n

For more information, see the Components\nsection of the Architecture Overview page.

\n
\n

Dependency injectionlink

\n \n MovieListCtrl.$inject = ['MovieService'];\n function MovieListCtrl(movieService) {\n }\n \n

In AngularJS, you pass in any dependencies as controller function arguments.\nThis example injects a MovieService.

\n

To guard against minification problems, tell Angular explicitly\nthat it should inject an instance of the MovieService in the first parameter.

\n 		\n

Dependency injectionlink

\n

\nconstructor(movieService: MovieService) {\n}\n\n

\n

In Angular, you pass in dependencies as arguments to the component class constructor.\nThis example injects a MovieService.\nThe first parameter's TypeScript type tells Angular what to inject, even after minification.

\n

For more information, see the Dependency injection\nsection of the Architecture Overview.

\n
\n\n

Style sheetslink

\n

Style sheets give your application a nice look.\nIn AngularJS, you specify the style sheets for your entire application.\nAs the application grows over time, the styles for the many parts of the application\nmerge, which can cause unexpected results.\nIn Angular, you can still define style sheets for your entire application. But now you can\nalso encapsulate a style sheet within a specific component.

\n\n \n \n \n \n \n \n \n \n \n \n \n \n
\n AngularJS\n \n Angular\n
\n\n \n <link href=\"styles.css\" rel=\"stylesheet\" />\n \n

AngularJS, uses a link tag in the head section of the index.html file\nto define the styles for the application.

\n 		\n

Styles configurationlink

\n

\n\"styles\": [\n \"styles.css\"\n],\n\n

\n

With the Angular CLI, you can configure your global styles in the angular.json file.\nYou can rename the extension to .scss to use sass.

\n

StyleUrlslink

\n

In Angular, you can use the styles or styleUrls property of the @Component metadata to define\na style sheet for a particular component.

\n

\nstyleUrls: [ './movie-list.component.css' ],\n\n

\n

This allows you to set appropriate styles for individual components that won’t leak into\nother parts of the application.

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\n\n \n
\n\n\n" }