p-iterate/dist/index.js

Iterate over promises as they're fulfilled.

export async function* pIter(promises) {
    // Typescript incorrectly narrows `state` on the assumption that it doesn't
    // leak, so we manually widen it to its full type range.
    // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
    let state = { label: 'accumulating', values: [] };
    let count = 0;
    for (const promise of promises) {
        count++;
        /* eslint-disable @typescript-eslint/no-loop-func */
        Promise.resolve(promise)
            .then((value) => {
            if (state.label === 'yielded') {
                state.resolve(value);
                state = { label: 'accumulating', values: [] };
            }
            else if (state.label === 'accumulating') {
                state.values.push(value);
            }
        })
            .catch((error) => {
            if (state.label === 'yielded') {
                state.reject(error);
            }
            else if (state.label === 'accumulating') {
                state = { label: 'rejected', reason: error };
            }
        });
        /* eslint-enable @typescript-eslint/no-loop-func */
    }
    while (count > 0) {
        count--;
        if (state.label === 'rejected') {
            throw state.reason;
        }
        else if (state.label === 'accumulating') {
            if (state.values.length > 0) {
                yield state.values.pop();
            }
            else {
                // eslint-disable-next-line @typescript-eslint/no-loop-func
                yield new Promise((resolve, reject) => {
                    state = { label: 'yielded', resolve, reject };
                });
            }
        }
    }
}
function* map(iterable, fn) {
    let index = 0;
    for (const item of iterable) {
        yield fn(item, index++);
    }
}
export function pIterSettled(promises) {
    return pIter(map(promises, async (promise, index) => {
        try {
            return { status: 'fulfilled', value: await promise, index };
        }
        catch (error) {
            return { status: 'rejected', reason: error, index };
        }
    }));
}
export function pIterEnumerated(promises) {
    return pIter(map(promises, async (promise, index) => [
        index,
        await Promise.resolve(promise),
    ]));
}
//# sourceMappingURL=index.js.map