CODEWITHSUNDEEP
javascriptparallel-processingpromisebluebird
Spencer
Spencer

Reputation: 33

Parallel execution of Promises with return values

I want to call the queryDatabase function in parallel for each member in the resellers array, but cannot seem to find a way to do this given each call returns a value in the 'then' section...When I take away the await, the log prints empty because the promises didnt finish, but I believe the await makes it sequential

  // TODO: MAKE PARALLEL
  async function findOrgs(resellers) {
    var ao = [];
    for(const rese of resellers) {
      await queryDatabase(rese)
      .then((results) => {
          ao = ao.concat(results.map(re => re._id));
      })
    }
    console.log("done!", ao);
  }

Is it possible to make this parallel?

Upvotes: 2

Views: 114

Answers (1)

CertainPerformance
CertainPerformance

Reputation: 370689

Use Promise.all instead:

async function findOrgs(resellers) {
  const idArrs = await Promise.all(resellers.map((rese) => (
    queryDatabase(rese)
      .then(results => results.map(({ _id }) => _id))
  )))
  const ao = [].concat(...idArrs);
  console.log("done!", ao);
}

Upvotes: 2

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