ts如何声明类的泛型

class Test {

  value: number | number[];



  constructor(value: number | number[]) {

    this.value = value;

  }



  get computedValue() {

    if (typeof this.value === 'number') return this.value * 2;

    if (Array.isArray(this.value)) return this.value.map(i => i * 2);

  }

}

type TestProps = number | number[]



class Test {

  constructor(value: T) {

    this.value = value;

  }



  value: T;



  get computedValue(): T {

    if (typeof this.value === 'number') {

      return this.value * 2;

// error->Type 'number' is not assignable to type 'T'.

    }

    if (Array.isArray(this.value)) {

      return this.value.map(i => i * 2);

// error->Type 'number[]' is not assignable to type 'T'.

    }

  }

}



const test = new Test(1);

const test2 = new Test([1, 2]);



const num1: number = test.computedValue;

const num2: number[] = test2.computedValue;