LWC Decorators Best explanation

Decorators

The Lightning Web Components programming model has three decorators that add functionality to a property or function.

The ability to create decorators is part of ECMAScript, but these three decorators are unique to Lightning Web Components.

@api

To expose a public property, decorate a field with @api. Public properties define the API for a component.

See Public Properties.

To expose a public method, decorate it with @api. Public methods are part of a component’s API. To communicate down the containment hierarchy, owner and parent components can call JavaScript methods on child components.

See Public Methods.

@track

Fields are reactive. If a field’s value changes, and the field is used in a template or in a getter of a property that’s used in a template, the component rerenders and displays the new value.

There is one use case for @track. When a field contains an object or an array, there’s a limit to the depth of changes that are tracked. To tell the framework to observe changes to the properties of an object or to the elements of an array, decorate the field with @track.

See Fields.

@wire

To read Salesforce data, Lightning web components use a reactive wire service. When the wire service provisions data, the component rerenders. Components use @wire in their JavaScript class to specify a wire adapter or an Apex method.

See Understand the Wire Service and Call Apex Methods