Function retry

When an asynchronous iterable rejects, it retries getting the value specified number of times.

Note that retries deplete values prior the operator that threw the error, and so it is often used in combination with operator repeat.

import {pipe, toAsync, tap, retry} from 'iter-ops';

const i = pipe(
    toAsync([1, 2, 3, 4, 5, 6, 7, 8, 9]),
    tap(value => {
        if (value % 2 === 0) {
            throw new Error(`fail-${value}`); // throw for all even numbers
        }
    }),
    retry(1) // retry 1 time
);

for await(const a of i) {
    console.log(a); // 1, 3, 5, 7, 9
}
Copy

Above, we end up with just odd numbers, because we do not provide any repeat logic, and as a result, the retry simply jumps to the next value on each error.

Throws

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

See

• repeat

When an asynchronous iterable rejects, the callback is to return the flag, indicating whether we should retry getting the value one more time.

The callback is only invoked when there is a failure, and it receives:

• index - index of the iterable value that we failed to acquire
• attempts - number of retry attempts made so far (starts with 0)
• state - state for the entire iteration session

Note that retries deplete values prior the operator that threw the error, and so it is often used in combination with operator repeat.

Throws

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

See

• repeat