Type Inference

TypeScript is a statically typed language, which means that the type of a variable must be specified at the time of declaring it. Type inference is a feature of TypeScript that allows the type of a variable to be automatically determined based on the value assigned to it. This is particularly useful when working with complex types, such as interfaces and classes, as it allows you to write code that is more concise and easier to read.
For example, consider the following code written in TypeScript:

let x = 10;

In this code, the type of the x variable is inferred to be number , based on the value assigned to it. This means that you don’t have to explicitly specify the type of the x variable, making your code more concise and easier to read.
Type inference is not limited to simple types like number and string . It can also be used with complex types, such as interfaces and classes (we will talk more about interfaces on the upcoming chapters). For example, consider the following code:

interface Point {
  x: number;
  y: number;
}
let p: Point = { x: 10, y: 20 };

In this code, the type of the p variable is inferred to be Point , based on the value assigned to it. This means that you don’t have to explicitly specify the type of the p variable, making your code more concise and easier to read.
One of the key benefits of type inference is that it allows you to write code that is more flexible and adaptable. For example, if you need to change the type of a variable, you can simply assign a new value to it, and the type will be inferred based on the new value. This is much easier than having to manually update the type declaration every time you make a change to a variable.

In summary, type inference is a powerful feature of TypeScript that allows you to write more concise and readable code. It makes it easier to work with complex types, and allows your code to be more flexible and adaptable.