jest 中如何 mock 类其中的部分函数？`

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import { Recorder, Pubsub } from "trident"; const pubsub = new Pubsub(); export class SmartRecorder extends Recorder { constructor(props) { super(props); } start() { pubsub.subscribe('androidData', androidDataHandler); return super.start(); } }

使用 mockImplementation 方式，提示 类型“typeof Recorder”上不存在属性“mockImplementation” 用 as转换后无效。使用 jest.requireActual，直接没法运行。

试了两天搜了很多方法都不行，请问下大佬们怎么编写啊？

PUBSUB

recorder

props

3 replies 2021-01-26 15:22:22 +08:00

theohateonion

Jan 26, 2021

建议贴下测试代码先

Flands

Jan 26, 2021

test
```ts
const mockStart = jest.fn();
const mockInit = jest.fn();
const mockPublish = jest.fn();
const mockSubscribe = jest.fn();

// 第一种
import { Pubsub, Recorder } from "trident";

jest.mock("trident", () => {
return {
Pubsub: () => {
return class {
publish() {
return mockPublish;
}
subscribe() {
return mockSubscribe;
}
};
}
};
});

// 第二种
import * as trident from "@cloud/trident-js-sdk/src";

const mockPubsub = jest.spyOn(trident, "Pubsub");
(mockPubsubas jest.Mock).mockImplementation(() => {
return {
publish: mockPublish,
subscribe: mockSubscribe
};
});

const mockRecorder = jest.spyOn(trident, "Recorder");
(mockRecorder as jest.Mock).mockImplementation(() => {
const original = jest.requireActual('@cloud/trident-js-sdk/src');
return {
...original,
start: mockStart,
};
});

```

主要还是 `mockImplementation` 和 `requireActual`各种组合起来，虽然看着挺离谱也没法运行，但尝试了很多写法都不行。。

Flands

Jan 26, 2021

不要在意 `@cloud/trident-js-sdk/src` 这个，原本打算脱敏的，结果没脱全。实际上都是 `trident`