Advanced TypeScript Features in Angular

TypeScript is a superset of JavaScript that provides static typing, interfaces, and other advanced features. In Angular, leveraging TypeScript features can significantly improve code quality, maintainability, and developer experience.

Generics allow you to create reusable components and functions that work with any data type while retaining the information about that type.

For example:

function identity<T>(arg: T): T {
    return arg;
}

let output = identity<string>("myString");
            

Decorators are a special kind of declaration that can be attached to a class, method, accessor, property, or parameter. In Angular, decorators are widely used to define components, services, and modules.

Example of a component decorator:

import { Component } from '@angular/core';

@Component({
    selector: 'app-example',
    templateUrl: './example.component.html',
    styleUrls: ['./example.component.css']
})
export class ExampleComponent {
    // Component logic
}
            

Mapped types allow you to create new types by transforming properties of an existing type. This is particularly useful for creating variations of existing types.

type Readonly = {
    readonly [K in keyof T]: T[K];
};

type User = {
    name: string;
    age: number;
};

type ReadonlyUser = Readonly; // All properties are readonly
            

Conditional types allow you to express non-uniform type mappings, making them very powerful for creating types that depend on other types.

type IsString = T extends string ? "Yes" : "No";

type A = IsString; // "Yes"
type B = IsString; // "No"