Debounced channel

debounced-channel.js

//usage example:
function* watchChangeAction() {
   const changeActionChannel = yield actionChannel(actionTypes.CHANGE);
   const requestChannel = yield call(debouncedChannel, 300, changeActionChannel);
  // handleRequest will be called with the debounced actions
   yield fork(handleRequest, requestChannel)
}


export function* debouncedChannel(ms, originalChannel) {
    const newChannel = yield call(channel);
    yield spawn(debounceAction, ms, originalChannel, newChannel);

    return newChannel;

}


function* debounceAction(ms, originalChannel, targetChannel) {
    while(true) {
        let didEnoughTimePass = false;
        let action = yield take(originalChannel);
        while(!didEnoughTimePass) {
            didEnoughTimePass = yield call(function*() {
                const {anotherAction, enoughTimeHasPassed} = yield race({
                    anotherAction: take(originalChannel),
                    enoughTimeHasPassed: delay(ms).then(() => true)
                });
                if (enoughTimeHasPassed) {
                    return true;
                } else {
                    action = anotherAction;
                    return false;
                }
            });
        }
        // once enough time has passed
        yield put(targetChannel, action);
    }

}