Angular - bind public/private properties

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I'm doing angular tutorial at, where I read:

constructor(**public** messageService: MessageService) {}

The messageService property must be public because you're about to bind to it in the template.

Angular only binds to public component properties.

I emphasize public there.

However, if I change public to private there, everything works as before...

So please guide me to place where I can dispel my doubts.

My Angular version: 5.0.0,

Thank you!

This is just a recommendation so that your project is compatible with AOT (Ahead Of Time) type build process. You can see its impact by creating an AOT build with this command:

ng build --prod

AOT Compiler requires public properties, while non-AOT allows , Angular should require that all component properties be public. in near future, it will be possible to binding private properties in v6 ivy app or  property binding uses the square brackets to indicate to Angular the property of an element that should be updated when the data-bound variable changes. The element could be an HTMLElement ( span, h1, input, etc) or a Component element (a custom element defined using the @Component decorator).

If you used Angular CLI to build your application, at some version CLI would swallow the errors that Angular would throw when building an app. With the CLI update they started showing the errors to the user eventually and stopping the application from building successfully.

Check this issue on GitHub for more information.

Clarity and/or discussion on "private" property/method naming , Docs or bug report Description I was hoping to gain more with public properties. additionally _ will make the private properties sort to add support for AOT compilation of binding to protected component fields,  The DOM representation of the hidden attribute is a property also called hidden, which if set to true hides the element and false shows the element. Angular doesn’t manipulate HTML attributes, it manipulates DOM properties because the DOM is what actually gets displayed. So when we write [hidden]

Yes you're right, but in production mode you can't change public to private.

this show the error in production mode

One-way property binding mechanism in Angular, Data binding in Angular works by synchronizing the data in the Property binding is the primary way of binding data in Angular. constructor(private child: Child) { this.title = 'app' } public changeTitle(newTitle: string) { The fact that it works fine even when properties are declared private is an unfortunate by-product of Angular 2 emitting compiling to JavaScript which has no private properties. A user of Angular 2 should not need to know that private is not supposed to work (but actually works due to the oddities of JavaScript).

Component interaction, Pass data from parent to child with input binding · Intercept input property NameChildComponent { private _name = ''; @Input() set name(name: string) { this. Property binding flows a value in one direction, from a component's property into a target element property. You can't use property binding to read or pull values out of target elements. Similarly, you cannot use property binding to call a method on the target element. If the element raises events, you can listen to them with an event binding.

Attribute directives, Attribute directives are used as attributes of elements. onMouseLeave() { this.​highlight(null); } private highlight(color: string) { this.el. It's called an input property because data flows from the binding expression into the directive. tells Angular that this property is public and available for binding by a parent component. Right to build gate across easement will vary case by case the easement becomes a public notice of the continuing obligation of the servient property, which is binding on subsequent owners of

Add services, Add a private heroService parameter of type HeroService to the constructor. The messageService property must be public because you're going to bind to it in​  The parent component cannot data bind to the child's start and stop methods nor to its seconds property. You can place a local variable, #timer, on the tag <countdown-timer> representing the child component. That gives you a reference to the child component and the ability to access any of its properties or methods from within the parent template.

  • AFAIK, AOT compilation will complaint about private property, AOT bundles are also preferred for prod build..