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mixins with parameters typescript

Homely Hoopoe answered on August 7, 2021 Popularity 2/10 Helpfulness 1/10

answer mixins with parameters typescript

mixins with parameters typescript

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// Utility types:

type GetProps<TBase> = TBase extends new (props: infer P) => any ? P : never
type GetInstance<TBase> = TBase extends new (...args: any[]) => infer I ? I : never
type MergeCtor<A, B> = new (props: GetProps<A> & GetProps<B>) => GetInstance<A> & GetInstance<B>


// Usage:
// bypass the restriction and manually type the signature
function GeometryMixin<TBase extends MixinBase>(Base: TBase) {
  // key 1: assert Base as any to mute the TS error
  const Derived = class Geometry extends (Base as any) {
    shape: 'rectangle' | 'triangle'
    constructor(props: { shape: 'rectangle' | 'triangle' }) {
      super(props)
      this.shape = props.shape
    }
  }

  // key 2: manually cast type to be MergeCtor
  return Derived as MergeCtor<typeof Derived, TBase>
}

Popularity 2/10 Helpfulness 1/10 Language typescript

Source: stackoverflow.com

Tags: mixins parameters typescript

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