How do I have an asynchronous variable inside a synchronous loop?

Question

The variable ids is an array with different spreadsheet ids. I wrapped it around the request because I want to do the same thing on multiple spreadsheets, however, once inside the request the id just becomes synchronous and stays as the last element in the ids array. I want to make it so that the id is asynchronous and changes so that I can do the request on multiple ids.

for(var i = 0; i < num; i++) {
      var id = ids.slice(i, i+1);
      var params = {
        spreadsheetId: id,
        ranges: ['A3:L'],
        includeGridData: true,
      };

      var request = gapi.client.sheets.spreadsheets.get(branchParams);
      request.then(function(response) {
        console.log(id);

Lucas D · Accepted Answer · 2020-07-09 03:29:40Z

2

Try this:

const getSheets = (ids) => {
  return Promise.all(
    ids.map(id => {
      const params = {
        spreadsheetId: id,
        <...>
      }
      return gapi.client.sheets.spreadsheets.get(params)
    })
  )
}

This will call the api once for every id in your list and return the list of responses in a promise. You can use this function like this:

const doStuffWithSheets = async () => {
  const ids = [1, 2, 3]
  const sheetResponses = await getSheets(ids);
  sheetResponses.forEach(response => {
    console.log(response)
  })
}

Some documentation for reference:

Promise.all(): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all

map(): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map

async function: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function

answered Jul 9, 2020 at 3:29

Lucas D

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2 Comments

Oskrskrr Over a year ago

I got this to work but how do I go about console.logging each id inside the forEach loop? Thanks.

Lucas D Over a year ago

It should be in the response. I think the response should look like this: developers.google.com/sheets/api/reference/rest/v4/… You can also use console.log(JSON.stringify(response, null, 2)); to print the full response and see whats inside

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