CODEWITHSUNDEEP
javascriptnode.jsexpresspromisebluebird
mcclosa
mcclosa

Reputation: 1455

Waiting on multiple map methods to return using promises and then get all maps return values

In an express project, I have 2 maps that both run through a puppeteer instance and both return arrays. Currently, I am using Promise.all to wait on both maps to finish, but it only returns the values from the first array and not the second. How can I do this so that I get both map variables results?

const games = JSON.parse(JSON.stringify(req.body.games));

const queue = new PQueue({
  concurrency: 2
});

const f = games.map((g) => queue.add(async () => firstSearch(g.game, g.categories)));
const s = games.map((g) => queue.add(async () => secondSearch(g.game, g.categories)));

return Promise.all(f, s)
  .then(function(g) {
    console.log(g); //only returns `f` result, not the `s`
  });

Upvotes: 0

Views: 413

Answers (2)

Benjamin Gruenbaum
Benjamin Gruenbaum

Reputation: 276306

There is no need to use a PQueue, bluebird already supports this out of the box:

(async () => {
  const games = JSON.parse(JSON.stringify(req.body.games));
  let params = { concurrency: 2};
  let r1 = await Promise.map(games, g => firstSearch(g.game, g.categories), params);
  let r2 = await Promise.map(games, g => secondSearch(g.game, g.categories), params);
  console.log(r1, r2);
 })();

Or more correctly but with more code (so the last - first search doesn't wait):

(async () => {
  const games = JSON.parse(JSON.stringify(req.body.games));
  let params = { concurrency: 2};
  let fns = [
    ...games.map(g => () => firstSearch(g.game, g.categories)),
    ...games.map(g => () => secondSearch(g.game, g.categories)),
  ];
  let results = await Promise.map(fns, fn => fn(), params);
  console.log(results);
 })();

Upvotes: 1

Shubham Khatri
Shubham Khatri

Reputation: 281686

Promise.all accepts an array of Promises as an argument. You need to pass on both arrays as a single array argument

return Promise.all(f.concat(s))
  .then(function(g) {
    console.log(g); //only returns `f` result, not the `s`
  });

Upvotes: 3

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