typescript 全部英语单词

TypeScript is a statically typed, object-oriented programming language developed and maintained by Microsoft. It builds on JavaScript and adds features like interfaces, classes, and type annotations to enhance developer productivity and catch errors at compile-time rather than runtime. Some key TypeScript concepts include:

1. **Interfaces**: Define contracts for objects, specifying the shape of data they should have, with properties and methods.

   interface Person {
       name: string;
       age: number;
   }

2. **Classes**: Represent reusable objects with properties (state) and methods (behaviors).

   class Car {
       brand: string;
       model: string;
       drive() { /* implementation */ }
   }

3. **Type Annotation**: Adding `:` followed by a type to specify the expected variable or function return type.

   let num: number = 5;
   function add(a: number, b: number): number { return a + b; }

4. **Generics**: Allow functions and classes to work with different types.

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

5. **Union Types**: Combining multiple types into one, allowing variables to hold any of those types.

   let color: 'red' | 'blue';

6. **Intersection Types**: Similar to unions but allows common properties between types.

   interface A { x: number; }
   interface B { y: string; }
   type C = A & B; // Both x and y are present

7. **Enums**: Specify a fixed set of named constants.

   enum Color { Red, Green, Blue }