Convert array of objects with Promise to normal array

Question

After using async-await I am getting the following console log. I am not sure what I am doing wrong.

[
  Promise {
    {
      categoryName: 'Salary',
      categoryAmount: '35000',
      categoryValue: 'salary',
      categoryId: '5f81c02c8e9fdf62f0422c09'
    }
  },
  Promise {
    {
      categoryName: 'Custom Category',
      categoryAmount: '70000',
      categoryValue: 'custom-category',
      categoryId: '5f841d47f4aaf1462cb6065f'
    }
  }
]

How can I convert this to a normal array of objects?

Like this:

[
      {
        categoryName: 'Salary',
        categoryAmount: '35000',
        categoryValue: 'salary',
        categoryId: '5f81c02c8e9fdf62f0422c09',
      },
      {
        categoryName: 'Custom Category',
        categoryAmount: '70000',
        categoryValue: 'custom-category',
        categoryId: '5f841d47f4aaf1462cb6065f',
      },
    ];

I was getting an array with pending promises

[ Promise { <pending> }, Promise { <pending> }, Promise { <pending> } ]

So I have used setTimeout to get the resolved promise.

Here's the Code:

exports.createBudget = async (req, res) => {
  //RevenueCategories
  const revenueData = await req.body.revenueCategories.map(async (el) => {
    //Check if Revenue exists in Revenue Model's Collection, if true get it's _id
    let currentDoc = await Revenue.findOne({
      categoryValue: el.categoryValue,
    }).select('_id');

    //if we have _id then assign it to categoryId property
    if (currentDoc !== null) {
      el.categoryId = await (currentDoc._id + '');
    } 

    //if new Revenue Category then create new Doc and assign it's _id to categoryId property
    else if (currentDoc === null) {
      let newCategData = {
        categoryName: el.categoryName,
        categoryValue: el.categoryValue,
      };

      let newCateg = await Revenue.create(newCategData);
      el.categoryId = await (newCateg._id + '');
    }

    return el;
  });

  setTimeout(async () => {
    console.log('Revenue Data', revenueData);

    const budgetDoc = {
      ...req.body.budgetData,
      revenueData,
    };

    const budget = await Budget.create(budgetDoc);

    res.status(201).json({
      data: {
        status: 'success',
        budget,
      },
    });
  }, 5000);
});

What is the mistake in my code that I am getting an array of promises rather than an array of Objects?

Please Help.

If you have an array of promises, you can get an array of their resolved values with const resolvedValue = Promise.all(promises); — TKoL
– TKoL, Commented Oct 12, 2020 at 13:45

TKoL · Accepted Answer · 2020-10-12 13:48:13Z

4

async function getValue(x) {
  await new Promise(r => setTimeout(r, 100)); // wait 100 ms
  return x * 2;
}

const promises = [];
promises.push(getValue(1));
promises.push(getValue(2));
promises.push(getValue(3));

// right now, promises is an array of promises -- let's turn that into values:
(async () => {
  const promiseValues = await Promise.all(promises);
  console.log('values:');
  console.log(promiseValues);
})();

That's how you can use Promise.all to turn an array of promises into an array of values

answered Oct 12, 2020 at 13:48

TKoL

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