Function wait

When the value is a Promise, it is resolved, or else returned as is, i.e. the same logic as for JavaScript operator await.

import {pipe, toAsync, map, wait} from 'iter-ops';

const userIds = [1, 2, 3, 4, 5]; // synchronous list of user id-s

const i = pipe(
    toAsync(userIds), // make pipeline asynchronous
    map(id => myService.getUserData(id)), // map into promises
    wait() // resolve each Promise
);

for await(const user of i) {
    console.log(user); // print details for each user
}
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In case you want all promises resolved before emitting values:

import {pipe, toAsync, map, aggregate, wait, spread} from 'iter-ops';

const userIds = [1, 2, 3, 4, 5]; // synchronous list of user id-s

const i = pipe(
    toAsync(userIds), // make pipeline asynchronous
    map(id => myService.getUserData(id)), // map into promises
    aggregate(list => Promise.all(list)), // resolve all promises
    wait(), // resolve the list
    spread() // emit each resolved value
);

for await(const user of i) {
    console.log(user); // print details for each user
}
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Throws

Error: 'Operator "wait" requires asynchronous pipeline' when used inside a synchronous pipeline.

See

• waitRace
• mapWait