这可能是一个奇怪的问题,但我很好奇是否有可能创建一个需要其中一个属性的接口。
所以,例如……
interface Message {
text: string;
attachment: Attachment;
timestamp?: number;
// ...etc
}
interface Attachment {...}
在上面的情况下,我想确保文本或附件都存在。
我现在就是这么做的。我觉得它有点啰嗦(为slack输入botkit)。
interface Message {
type?: string;
channel?: string;
user?: string;
text?: string;
attachments?: Slack.Attachment[];
ts?: string;
team?: string;
event?: string;
match?: [string, {index: number}, {input: string}];
}
interface AttachmentMessageNoContext extends Message {
channel: string;
attachments: Slack.Attachment[];
}
interface TextMessageNoContext extends Message {
channel: string;
text: string;
}
您可以为所需的条件创建一些接口,并将它们以如下类型连接起来:
interface SolidPart {
name: string;
surname: string;
action: 'add' | 'edit' | 'delete';
id?: number;
}
interface WithId {
action: 'edit' | 'delete';
id: number;
}
interface WithoutId {
action: 'add';
id?: number;
}
export type Entity = SolidPart & (WithId | WithoutId);
const item: Entity = { // valid
name: 'John',
surname: 'Doe',
action: 'add'
}
const item: Entity = { // not valid, id required for action === 'edit'
name: 'John',
surname: 'Doe',
action: 'edit'
}
有一些很酷的Typescript选项,你可以使用https://www.typescriptlang.org/docs/handbook/utility-types.html#omittk
你的问题是:创造一个既存在“文本”又存在附件的界面。你可以这样做:
interface AllMessageProperties {
text: string,
attachement: string,
}
type Message = Omit<AllMessageProperties, 'text'> | Omit<AllMessageProperties, 'attachement'>;
const messageWithText : Message = {
text: 'some text'
}
const messageWithAttachement : Message = {
attachement: 'path-to/attachment'
}
const messageWithTextAndAttachement : Message = {
text: 'some text',
attachement: 'path-to/attachment'
}
// results in Typescript error
const messageWithOutTextOrAttachement : Message = {
}
您可以为所需的条件创建一些接口,并将它们以如下类型连接起来:
interface SolidPart {
name: string;
surname: string;
action: 'add' | 'edit' | 'delete';
id?: number;
}
interface WithId {
action: 'edit' | 'delete';
id: number;
}
interface WithoutId {
action: 'add';
id?: number;
}
export type Entity = SolidPart & (WithId | WithoutId);
const item: Entity = { // valid
name: 'John',
surname: 'Doe',
action: 'add'
}
const item: Entity = { // not valid, id required for action === 'edit'
name: 'John',
surname: 'Doe',
action: 'edit'
}
我进一步压缩了@Voskanyan David的解决方案,得到了我个人认为非常简洁的解决方案:
你仍然需要在某个地方定义Only<>和Either<>
type Only<T, U> = {
[P in keyof T]: T[P];
} & {
[P in keyof U]?: never;
};
type Either<T, U> = Only<T, U> | Only<U, T>
之后,可以在没有任何中间接口/类型的情况下定义它:
type Message {
type?: string;
channel?: string;
user?: string;
// ...etc
} & Either<{message: string}, {attachment: Attachment}>