在typescirpt中推断一个返回值

Question

想对Rule3的情况做更详细的类型推断，求解

export interface BaseOption {
    required?:
        | {
              message?: string

              tip?: string
          }
        | true
}

export type Validator = {
    [key in string]?: (val: number, formData: string, callback, props) => void | Promise<void | Error>
}

export interface RequiredFunc {
    required: (message: string) => void | Promise<void | Error>
}

export type CombineOptions<ExtraOption extends Validator> = ExtraOption & RequiredFunc

import { BaseOption, CombineOptions, Validator } from './type/index'

function Rule<ExtraOption extends Validator>(options: ExtraOption | BaseOption) {
    return {} as ExtraOption extends BaseOption ? CombineOptions<ExtraOption> : ExtraOption
}

const rule1 = Rule({
    a() {},
})

rule1.a // 有提示

const rule2 = Rule({ required: true })

rule2.required // 有提示

// 如果不手动加入Rule的泛型，下面的情况a没有代码提示
const rule3 = Rule({
    a(f, b) {},
    required: true,
})

rule3.required // 有提示
rule3.a // 无提示

Answer 1

已经解决了
https://stackoverflow.com/que...