[Best practices] setImmediate/ setTimeout is a good way to fix async work within IT case ?

[sanriqing]

💬 Questions and Help

It's ok to use setTimeout or setImmediate to wait some async work done ?

here is a example

// Component file::
class Demo extends React.Component {
   state ={data:''}
    async componentDidMount(){
        const data = await api.getData()
        this.setData({data})
    }
    render() {
        const {data} = this.state;
        return <div data-test-automation-id="test">{data}</div>;
    }
}

// test file
describe('Demo', () => {
    it('should render correct data', async () => {
         jest.spyOn(api,'getData').mockResolvedValue('testData');
        const {getByTestId} = render(<Demo/>)
        // we directly use getByTestId will be fail . you see , data still is ''
        // it's a good way to setImmediate to wait api called done?
        // or should we use rerender  / unmount to fix it ?
        await new Promise(setImmediate)
        expect(getByTestId('test')).toHaveTextContent('testData');
    });
});

we met many many scenarios like this.
like: show alert after save done

Looking forward to answers , thank you .

[sanriqing]

yeh, waitFor api called is fine in this case , but sometime we didn't export the async work out to check weather it have been called.

[Smrtnyk]

I don't get how can you pass in setImmediate as executor for a Promise?
Shouldn't it be

await new Promise((resolve) => {
                setImmediate(resolve);
            });

Also setImmediate is removed from a global in jsdom in jest 27, so you would want to import setImmediate from "timers"

[sanriqing]

I don't get how can you pass in setImmediate as executor for a Promise?
Shouldn't it be

await new Promise((resolve) => {
                setImmediate(resolve);
            });

Also setImmediate is removed from a global in jsdom in jest 27, so you would want to import setImmediate from "timers"

yeh.... What's i want to say is set a timer to wait for microtasks have been done . setImmediate is not necessary ，setTimeout is ok too. Much thanks for answer.

[sanriqing]

ref: #2157

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