如何扩展和接口已经在打字中设置？

Question

In D3 it's common to add attributes to already existing D3 variables.

An example (ES5):

force = d3.layout.force()
  .nodes([{ links: 0, color: '#2BC9E9' }])

The error:

Argument of type '{ links: number; color: string; }[]' is not assignable to
parameter of type 'Node[]'.

If we could create a new interface we would simple do:

interface Node_ extends Node {
    links: number;
    color: string;
}

How do we extend the interface Node already defined in D3's typings to allow for the new attributes ?

Answer 1

Typescript allows split interface declaration into multiple files. So you can just add bellow definition anywhere in your code

declare namespace d3 {
    namespace layout {
        namespace force {
            interface Node {
                links?: number;
                color?: string;
            }
        }
    }
}

This way new interface definition (Node_) is not needed