将Promises Code转换为async等待和模拟测试用例? [英] Converting Promises Code to async await and mocking test cases?

问题描述

如何将嵌套了promise和await的以下函数转换为仅使用await或仅使用promise?

How to convert the below function which has nested promise and await to just using await or only using promises ?

const test = (url, id) => {
  return new Promise((_resolve, _reject) => {
    if (isValidUrl(url)) {
      let storage = new Storage(Indexdb, id);
      const cae = new valueExtract(url);
      cae.fetch()
        .then(data => {
          new zip(data)
            .then(obj => obj.getZip())
            .then(obj => obj.getList())
            .then(list => {
              return new Promise(async (resolve, reject) => {
                try {
                  let sI = storage.connection;
                  await Promise.all(Object.keys(list).map(async (fileName, index) => {
                    let blob = await new FileExtractor(list[fileName]);
                    await sI.setItemForce(
                      fileName,
                      new StoreObject(
                        fileName,
                        'testData',
                        blob
                      ).dataObject
                    )
                  }))
                  _resolve(sI);
                } catch (err) {
                  _reject(err)
                }
              })
            })
            .catch(err => _reject(err))
        })
        .catch(err => _reject(err))
    } else {
      _reject('Invalid URL')
    }
  })
};

我无法做到这一点，但无法解决

I was unable to do the same this what i tried but it never resolves

const test = async (url, id) => {
  if (isValidUrl(url)) {
    try {
      let storage = new Storage(Indexdb, id);
      const cae = new valueExtract(url);
      const data = await cae.fetch();
      return new ZIPExtractor(data)
        .then(obj => obj.getZip())
        .then(obj => obj.getList())
        .then(list => {
          return async (resolve, reject) => {
            try {
              let sI = storage.connection;
              await Promise.all(Object.keys(list).map(async (fileName, index) => {
                let blob = await new FileExtractor(list[fileName]);
                await sI.setItemForce(
                  fileName,
                  new StoreObject(
                    fileName,
                    'testData',
                    blob
                  ).dataObject
                )
              }))
            } catch (err) {
              throw new Error(err)
            }
          }
        })
        .catch(err => _reject(err))
    } catch (e) {
      throw new Error('Invalid URL')
    }
  }
};

我们还应该如何为此类函数编写测试用例，以使我们无需传入实际的网络url并开玩笑.

Also how do we write test case for these kind of a function so that we need not pass in actual network url and mock in jest.

推荐答案

应该完成，但您必须return使用async (resolve, reject) { … }.您永远不应该首先使用它，您可以忽略它:

It should fulfill, but with the async (resolve, reject) { … } that you return. You never should've used this in the first place, you can just omit it:

const test = async (url, id) => {
  if (!isValidUrl(url)) {
    throw new Error('Invalid URL')
  }
  const storage = new Storage(Indexdb, id);
  const cae = new valueExtract(url);
  const data = await cae.fetch();
  const obj = await new ZIPExtractor(data); // shudder. A constructor should never return a promise
  const zip = await obj.getZip();
  const list = await zip.getList();
  const sI = storage.connection;
  await Promise.all(Object.keys(list).map(async (fileName, index) => {
    const blob = await new FileExtractor(list[fileName]);
    const store = new StoreObject(fileName, 'testData', blob);
    await sI.setItemForce(fileName, store.dataObject);
  }));
  return sI; // or something?
}

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