Data binding
The simplest form of binding is string interpolation, which uses double curly braces {{ expression }}. This template expression is evaluated and then converted to string by Angular. It can take expressions such as {{ 'Hell' + 'o' }} which outputs Hello, or {{ 100 === 100 }} which returns a Boolean of true. It can even contain functions such as {{ 1 + getAge() }}.
Here's another case where we use a template expression that references a template input variable {{ feed }}:
<li *ngFor="let feed of feeds" (click)="show(feed)">{{ feed }}</li>
When the user interacts with a view, it's often required to intercept these events and perform some activity. The events such as click can be intercepted by surrounding the event name in parentheses and assigning it to a handler of the event, such as show(...). You can have other types of binding, such as property binding, which is used for binding to the property of an element or component. The syntax is of the form [property]="......
