Typescript 将空函数反应为 defaultProps
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Typescript React empty function as defaultProps
提问by Fabrice
I have a Stateless Functional Component with an optional function parameter as property (onClick), I tried to define an empty function as default property to be able to do safely in my component :
我有一个带有可选函数参数作为属性 (onClick) 的无状态功能组件，我尝试将一个空函数定义为默认属性，以便能够在我的组件中安全执行：
<span onClick={props.onClick} />
But I have the following error : 'Expression expected.'
但我有以下错误：“预期表达。”
interface IProps {
size?: sizeType;
onClick?: (e:any) => void;
}
const Foo: React.SFC = (props: IProps) => {
// ...
};
const defaultProps: IProps = {
size: 'default',
onClick: () => void <-- Expression expected.
};
Foo = defaultProps;
How can I should do this?
我该怎么做？
回答by Daniel Derevjanik
You cannot use voidin javascript as return value. Instead of void, use nullas return value.
您不能void在 javascript 中使用作为返回值。代替void，null用作返回值。
onClick: () => null
回答by Remo H. Jansen
You can use the following:
您可以使用以下内容：
const defaultProps: IProps = {
size: 'default',
onClick: () => void(0)
};
回答by Scott Stern
I think using lodashes noop might be a good option because depending on the number of re-renders the component will have BEFORE the component has access to the prop, it will create that many references to an anonymous function that essentially is a place holder for the function you need. Something like:
我认为使用 lodashes noop 可能是一个不错的选择，因为根据组件在组件访问 prop 之前的重新渲染次数，它将创建对匿名函数的许多引用，该函数本质上是一个占位符你需要的功能。就像是：
import noop from 'lodash/noop';
MyComponent.defaultProps = {
myfunc: noop,
};
Its a small optimization but also prevents the developer from creating an anonymous function for every default prop declaration that a func is needed in.
它是一个小的优化，但也阻止了开发人员为每个需要 func 的默认 prop 声明创建匿名函数。
回答by 1252748
I usually do
我通常做
MyComponent.defaultProps = {
someNoop: f => f
}
as something that is short, easy to type, and will just return undefined.
作为简短、易于输入且只会返回的内容undefined。
