Clash Royale CLAN TAG#URR8PPP

Synchronic code with map functions

I think I got totally lost, I thought I had at least some grasp on async stuff, but this particular case got me confused.

I perform a search on the database and expect an array of results.
Then i map through the array, check for flag and push info to the array.

However, I'm doing async calls wrong, because when I console log the finalData it's always empty, therefore it resolves before it should.

Here are my attempts, tried it both ways:

let finalData = ;

let lastWeek = new Date();
lastWeek.setDate(lastWeek.getDate() - 7);

db.find( createdAt: "$gte": lastWeek ).then((records, err) =>

async function test()
let array = _.map(records, (record) =>
db2.find( 'foo': record.id ).then((bar, err) =>

if (bar.endDate)
let data = `Email: $record.email`;
finalData.push(data);
else
let data = `Email: $record.email`;
finalData.push(data);

);
);

await Promise.all(array).then(() =>
console.log(finalData);
);



test();
);


and:

db.find( createdAt: "$gte": lastWeek ).then((records, err) =>

let promise1 = new Promise((resolve, reject) =>
_.map(records, (record) =>
db2.find( 'foo': record.id ).then((bar, err) =>

if (bar.endDate)
let data = `Email: $record.email`;
finalData.push(data);
else
let data = `Email: $record.email`;
finalData.push(data);

);
);

resolve();
);

promise1.then(() =>
console.log(finalData);
)
);


Results are the same, I'm doing something wrong.

map

forEach

for loop

map

forEach

for..of

1 Answer
1

return

map

array

undefined

finalData

push

Promise.all

then

err

then

async

await

let lastWeek = new Date();
lastWeek.setDate(lastWeek.getDate() - 7);

const records = await db.find( createdAt: "$gte": lastWeek );
let promises = records.map(async (record) =>
const bar = await db2.find( 'foo': record.id );
if (bar.endDate)
return `Email: $record.email`;
else
return `Email: $record.email`;

);

const finalData = await Promise.all(promises)
console.log(finalData);


Or alternatively:

let lastWeek = new Date();
lastWeek.setDate(lastWeek.getDate() - 7);

return db.find( createdAt: "$gte": lastWeek ).then(records =>
let promises = records.map(record =>
return db2.find( 'foo': record.id ).then(bar =>
// ^^^^^^
if (bar.endDate)
return `Email: $record.email`;
// ^^^^^^
else
return `Email: $record.email`;
// ^^^^^^

);
);
return Promise.all(promises);
// ^^^^^^
).then(finalData =>
console.log(finalData);
);


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