javascript - Redux Thunk handling network responses in a different order -


i have text entry field (via thunk) queries server of validity of user's text. these requests can happen in quick succession, may returned server in different order when sent. therefor, string in text field may shown invalid, when in fact valid.

to fix this, i'm performing check when receive response server - current content of text field same checked? if not, check again. feel there should better way handle situation querying dom element value.

how can follow through pre post server request?

export function updateusercode(code) {     return dispatch => {         return dispatch(validateusercode(code))     } }  function validateusercode(code) {     return dispatch => {         dispatch(updatecode(code))         return fetch(`/api/code/${code}`)             .then(response => response.json())             .then(json => dispatch(receivevalidatedcode(code, json)))             .catch(error => {log.error(error)})     } }  function receivevalidatedcode(code, data) {     const lastval = document.getelementbyid('usercode').value     if (code != lastval) {         // code not same current value         // need validate again         return updateusercode(lastval)     }     if(data.success) {         return {             type: types.code_validated,             code: code,         }     }     return {         type: types.code_invalid,         reason: data.reason,     } }

messing dom inside logic indeed less ideal. suggest keeping last entered text field value in redux store , perform checks in reducer.

also don't see point in re-validating user input if current entered value differs 1 validated last resolved request. ignore such responses , not perform unnecessary request.

in terms of code can that:

// actions const requestvalidation = value => ({ type: 'request-validation', value });  const receivevalidation = (value, result) => ({ type: 'receive-validation', value, result });  export const validateusercode = code => dispatch => {   dispatch(requestvalidation(code));   return fetch(`/api/code/${code}`)          .then(response => response.json())          .then(json => dispatch(receivevalidation(code, json)))          .catch(error => {log.error(error)}) }  // reducer export const validationreducer = (state = {}, action) => {   if (action.type === 'request-validation')      return ({ value: action.value, isvalidating: true });    if (action.type === 'receive-validation' && state.value === action.value)      return ({ value: action.value, isvalid: !!action.success });    return state;  };

that not production quality code, , don't event sure if works, reflects idea.


Comments

Post a Comment

Popular posts from this blog

inversion of control - Autofac named registration constructor injection -

does autofac support specifying registration name in components' constructors? example: ninject's namedattribute . you need use autofac.extras.attributed package on top achieve this so let's have 1 interface , 2 classes: public interface ihello { string sayhello(); } public class englishhello : ihello { public string sayhello() { return "hello"; } } public class frenchhello : ihello { public string sayhello() { return "bonjour"; } } then have consumer class, in want select instance injected: public class helloconsumer { private readonly ihello helloservice; public helloconsumer([withkey("en")] ihello helloservice) { if (helloservice == null) { throw new argumentnullexception("helloservice"); } this.helloservice = helloservice; } public string sayhello() { return this.helloservice.sayhello()...
Read more

verilog - Systemverilog dynamic casting issues -

i've code snippet following in testbench function void write_to_port( my_data_type_base data ); my_data_type_extended data_ext; if(!$cast(data_ext, data)); `uvm_error(get_type_name(), "failed cast"); `uvm_info(get_name(), $psprintf("data_ext :\n%s", data_ext.sprint()), uvm_medium) // write data_ext out port.... endfunction when run it, i'm getting uvm_error "failed cast." i'm not quire sure why $cast not returning 1. can see, i'm printing out extended class data item after casting uvm_info. can see it's being cast properly. if don't use $cast if condition, don't runtime error. isn't coding practice use if dynamic cast check if $cast returning 1 ? what might reason behind cast not returning 1 in above case? i think semicolon on line 'if' not belong? i think consumes if statement, , uvm_error executes regardless of how if evaluates: if(!$cast(data_ext, data)); <- no semico...
Read more

ios - Change Storyboard View using Seague -

i have following code checks connection server, , depending on want change views if no connection found. nsstring *connect = [nsstring stringwithcontentsofurl:[nsurl urlwithstring:@"http://myserver.com"] encoding:nsutf8stringencoding error:nil]; if (connect == null) { [self performseguewithidentifier:@"network_failure" sender:self]; } else { // other code here } my problem not change views. have added storyboard segue between 2 views identifier of network_failure . not have navigation controller or that, problem? thanks help! no not problem. first of all, in objectivec exists nil object oriented null . must use that. so: if(connect == nil) or better: if(!connect) so due fact nil not same of null , probably code does't enter in if scope . you have been able discover breakpoint. anyway: be sure set trigger segue (line) 2 view controller , , name network_failure (that not best name. should instead view1toview2 ) as, m...
Read more