Async / Await - Promise with Object map function

Question

I'm really confused. I tried to lot of things but I can't reach the correct result.

Here is scenario; I have list of products that I can do multiple choice and delete them one by one. I want to wait all items can be deleted then return me a count.

async delete (ids) {

    const res = await this.deleteProcess(ids);
    return res;

  },

  deleteProcess(ids) {

    let countS = 0;

    Object.assign(ids).map((id) => {

      axios({
        method: "DELETE",
        url: store.getters.getServerPath + "api/v1/product/" + id,
        headers: store.getters.getConfigHeaders,
        withCredentials: true
      }).then(function (response) {

        countS++;

      }).then(() => {

        console.log(countS);
        return countS;
      });

    });
  }

And call this function like this:

deleteSelected (id) {
                if (id !== undefined) {
                    this.selectedRows.push(id);
                }
                controller.delete(this.selectedRows).then(function (res) {

                    alert(res + " items deleted");
                });
            },

Result res is always returns undefined. But inside of deleteProcess console.log is displayed how many items were deleted.

CertainPerformance · Accepted Answer · 2019-01-23 08:40:56Z

2

You should use Promise.all instead, incrementing countS each time a response comes back

deleteProcess(ids) {
  let countS = 0;
  return Promise.all(ids.map((id) => (
    axios({
      method: "DELETE",
      url: store.getters.getServerPath + "api/v1/product/" + id,
      headers: store.getters.getConfigHeaders,
      withCredentials: true
    }).then(function (response) {
      countS++;
    })
  )))
  .then(() => countS);
}

But you may as well just count up the length of ids rather than keep an external countS variable:

.then(() => ids.length);

Also note that

Object.assign(ids)

doesn't do anything - the resulting expression is === to the original ids variable, so might as well just use the original variable.

You also might consider adding a catch when a problem occurs:

controller.delete(this.selectedRows)
  .then(function (res) {
    console.log(res + " items deleted");
  })
  .catch((err) => {
    console.log('error', err);
  });

answered Jan 23, 2019 at 8:40

CertainPerformance

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1 Comment

Yasin Yörük Over a year ago

Thanks a lot. This is the result want to reaching for. I'm little bit confusing right now but after some rest I'll again study on this methods.

bltcrew · Accepted Answer · 2019-01-23 10:04:45Z

0

Your deleteProcess method returns nothing, so res is undefined. If you want a code using fully the async/await pattern, and delete them one by one, you could do:

async deleteProcess(ids) {
  let countSuccess = 0;
  let countFailure = 0;
  for (const id of ids) {
     try {
       await axios({
         method: "DELETE",
         url: store.getters.getServerPath + "api/v1/product/" + id,
         headers: store.getters.getConfigHeaders,
         withCredentials: true
       });
       countSuccess++;
      } catch (error) {
       countFailure++;
      }
  }
  return countSuccess;
}

edited Jan 23, 2019 at 10:04

answered Jan 23, 2019 at 8:54

bltcrew

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