Typescript - 接口中的函数返回类型

Question

Trying to do this

interface SomeInterface {
    someProperty: string | () => JSX.Element
}

The property should be either a string or a Function that returns a JSX.Element . What's the proper syntax, if any?

Currently I'm doing the following as a better-than-nothing solution, but it's not what I want

interface SomeInterface {
    someProperty: string | Function
}

Answer 1

Yup this is correct with parenthesis :

interface SomeInterface {
    someProperty: string | (() => JSX.Element)
}


declare const s: SomeInterface

if (typeof s.someProperty === 'function') {
    s.someProperty() // JSX.Element
} else {
    s.someProperty // string
}

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