Extending Interfaces

Like classes, interfaces can extend each other. This allows you to copy the members of one interface into another, which gives you more flexibility in how you separate your interfaces into reusable components.

interface Shape {
  color: string;
}

interface Square extends Shape {
  sideLength: number;
}

let square = <Square>{};
square.color = "blue";
square.sideLength = 10;

An interface can extend multiple interfaces, creating a combination of all of the interfaces.

interface Shape {
  color: string;
}

interface PenStroke {
  penWidth: number;
}

interface Square extends Shape, PenStroke {
  sideLength: number;
}

let square = <Square>{};
square.color = "blue";
square.sideLength = 10;
square.penWidth = 5.0;

Links:

https://www.typescriptlang.org/docs/handbook/interfaces.html#extending-interfaces

doc_TypeScript

2016-10-04 19:25:13

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