Develop Reference

One Function for Multiple Variables

I am making a sign up sheet app. There are several time slots one can write their name into and submit, showing their name where they have entered it at the corresponding time.
So far I can only get the function to do one name at a time. Is there a way to have it do the same function but for each time slot? Each input field has a corresponding <li> where I wish the input.value to appear. I am trying a switch() to no avail here.
Any help would be greatly appreciated.
Thanks
function addName(e) {
switch(e) {
case 0:
scheduleThree.appendChild(document.createTextNode(inputThree.value));
storeNameInLocalStorage(inputThree.value);
break;
case 1:
scheduleThreeTwoFive.appendChild(document.createTextNode(inputThreeTwoFive.value));
storeNameInLocalStorage(inputThreeTwoFive.value);
break;
}
}
For reference this is the working code for the function to run once. I know there must be a way to do it without writing new functions for each of the 12 time slots.
function addName(e) {
if(inputThree.value === '') {
// alert('Please enter your name');
} else {
scheduleThree.appendChild(document.createTextNode(inputThree.value));
storeNameInLocalStorage(inputThree.value);
}
}
function storeNameInLocalStorage(name) {
let names;
if(localStorage.getItem('names') === null){
names = [];
} else {
names = JSON.parse(localStorage.getItem('names'));
}
names.push(name);
localStorage.setItem('names', JSON.stringify(names));
}
function getNames() {
let names;
if(localStorage.getItem('names') === null){
names = [];
} else {
names = JSON.parse(localStorage.getItem('names'));
}
names.forEach(function(name){
scheduleThree.appendChild(document.createTextNode(name));
inputThree.remove();
inputThreeParent.appendChild(document.createTextNode(name))
})
}

How do I ensure an array has no null values?

I would like test my Array (input value) before submit my form.
My array with value :
const fields = [
this.state.workshopSelected,
this.state.countrySelected,
this.state.productionTypeSelected,
this.state.numEmployeesSelected,
this.state.startAt
];
I've try this :
_.forEach(fields, (field) => {
if (field === null) {
return false;
}
});
alert('Can submit !');
...
I think my problem is because i don't use Promise. I've try to test with Promise.all(fields).then(());, but i'm always in then.
Anyone have idea ?
Thank you :)

The problem is that even though you're terminating the lodash _.forEach loop early, you don't do anything else with the information that you had a null entry.
Instead of lodash's _.forEach, I'd use the built-in Array#includes (fairly new) or Array#indexOf to find out if any of the entries is null:
if (fields.includes(null)) { // or if (fields.indexOf(null) != -1)
// At least one was null
} else {
// All were non-null
alert('Can submit !');
}
For more complex tests, you can use Array#some which lets you provide a callback for the test.
Live example with indexOf:
const state = {
workshopSelected: [],
countrySelected: [],
productionTypeSelected: [],
numEmployeesSelected: [],
startAt: []
};
const fields = [
state.workshopSelected,
state.countrySelected,
state.productionTypeSelected,
state.numEmployeesSelected,
state.startAt
];
if (fields.indexOf(null) != -1) {
console.log("Before: At least one was null");
} else {
console.log("Before: None were null");
}
fields[2] = null;
if (fields.indexOf(null) != -1) {
console.log("After: At least one was null");
} else {
console.log("After: None were null");
}

You do not need to use promises unless there is an asynchronous operation (for example if you are getting that array from your server).
If you already have that array you can do something like:
// Using lodash/underscore
var isValid = _.every(fields, (field) => (field!==null)}
// OR using the Array.every method
var isValid = fields.every((field)=>(field!==null))
// Or using vanilla JS only
function checkArray(array){
for(var i = 0; i < array.length ; i ++){
if(array[i]===null){
return false;
}
}
return true;
}
var isValid = checkArray(fields);
// After you get that value, you can execute your alert based on it
if(!isValid){
alert('Something went wrong..');
}

Try this simple snippet
var isAllowedToSubmit = true;
_.forEach(fields, (field) => {
if (!field) {
isAllowedToSubmit = false;
}
});
if(isAllowedToSubmit)
alert('Can submit !');

You can do that without library:
if (fields.some(field => field === null)) {
alert('Cannot submit');
} else {
alert('Can submit');
}

You don't need to use lodash, you can do this in simple vanilla javascript. Simply iterate over each field and if an error occurs set your errors bool to true
let errors = false;
fields.forEach(field) => {
if(field === null || field === '') {
errors = true;
}
});
if (!errors) {
alert('Yay no errors, now you can submit');
}
For an es6 you can use.
const hasNoError = fields.every((field, index, selfArray) => field !== null);
if (!hasNoError) {
alert('yay It works');
};
Have a look at Array.every documentation Array every MDN documentation

jQuery each with ajax call will continue before it's finished

I have some jQuery which uses an each loop to go through values entered in a repeated form field on a Symfony 3 CRM. There is a $.post which sends the entered value to a function that checks for duplicates in the database, and if it's a duplicate it adds something to an array, otherwise it adds a blank value to indicate it's not a dupe. Once these have been done, it then checks the final array and adds any errors to the error block to display to the user.
However, it seems that the array is ALWAYS blank and I belivee it's because it's running the code that displays the errors BEFORE it's actually finished getting the response.
Here is my code:
$('#puppy_form').on('submit', function() {
var bitch_errors = [];
var dog_errors = [];
// NOTE: Bitch and dog names need to be checked differently so we know which error is assigned to which input
$('.check_bitch_name').each( function(i, obj) {
// need to check each name for validity and duplication.
var entered_bitch_name = obj.value;
var pattern = /^[a-zA-Z,.]+\s[a-zA-Z,.]+(\s[a-zA-Z,.]+){0,}$/;
if(!pattern.test(entered_bitch_name)) {
bitch_errors[i+1] = "invalid";
} else {
// now to check for duplicates
$.post('/check-puppy-name', { name: entered_bitch_name }
).done(function (response) {
if(response == 'duplicate') {
bitch_errors[i+1] = "duplicate";
} else {
bitch_errors[i+1] = "";
}
});
}
});
$('.check_dog_name').each( function(i, obj) {
// need to check each name for validity and duplication.
var entered_dog_name = obj.value;
var pattern = /^[a-zA-Z,.]+\s[a-zA-Z,.]+(\s[a-zA-Z,.]+){0,}$/;
if(!pattern.test(entered_dog_name)) {
dog_errors[i+1] = "invalid";
} else {
// now to check for duplicates
$.post('/check-puppy-name', { name: entered_dog_name }
).done(function (response) {
if(response == 'duplicate') {
dog_errors[i+1] = "duplicate";
} else {
dog_errors[i+1] = "";
}
});
}
});
if(count(bitch_errors) == 0 && count(dog_errors) == 0) {
return true;
}
// loop through the errors and assign them to the correct input
$.each( bitch_errors, function( key, value ) {
if (value == "invalid") {
$('input[name="bitch_name['+key+']"]').parent().addClass('has-error');
$('input[name="bitch_name['+key+']"]').next('.error-message').html('Names must be at least two words, and only contain letters');
return false;
} else if(value == "duplicate") {
$('input[name="bitch_name['+key+']"]').parent().addClass('has-error');
$('input[name="bitch_name['+key+']"]').next('.error-message').html('Sorry, this name has already been taken');
return false;
}
});
$.each( dog_errors, function( key, value ) {
if(value != "") {
if (value == "invalid") {
$('input[name="dog_name['+key+']"]').parent().addClass('has-error');
$('input[name="dog_name['+key+']"]').next('.error-message').html('Names must be at least two words, and only contain letters');
return false;
} else if(value == "duplicate") {
$('input[name="dog_name['+key+']"]').parent().addClass('has-error');
$('input[name="dog_name['+key+']"]').next('.error-message').html('Sorry, this name has already been taken');
return false;
}
}
});
return false;
});
Basically, it first checks that the inputted name is valid, then posts off and checks for dupes. The issue is, even though it does the validity check (and prints errors accordingly) it seems to ignore the dupe check and carry on before it's even called back the first response.
How can I make sure it's finished it's checking before going on and adding the errors to the form? I've tried other solutions including attempting to implement the $.when functionality in jQuery but I don't really understand how to make it work. Any help appreciated.

First, write a function that returns an asynchronous promise to give you a value for one dog:
function checkDog(name) {
var pattern = /^[a-zA-Z,.]+\s[a-zA-Z,.]+(\s[a-zA-Z,.]+){0,}$/;
if(!pattern.test(name)) {
return $.Deferred().resolve("invalid");
} else {
return $.post('/check-puppy-name', { name: name } )
.then(function (response) {
if (response === 'duplicate') {
return 'duplicate';
} else {
return '';
}
});
}
}
Then you can write one that handles multiple dogs, also returning a promise (which won't itself be resolved until every dog has been checked):
function checkDogs(array) {
return $.when.apply($, array.map(checkDog));
}
Note that there's no DOM-related code yet. You can now write a function that gets the values from a bunch of DOM inputs and returns them in an array:
function getInputValues($selector) {
return $selector.get().map(function(el) {
return el.value;
});
}
So now (on submit) you can check your two sets of inputs and then finally when both of these are available, you can examine the results and update the DOM:
$('#puppy_form').on('submit', function() {
var bitch_names = getInputValues($('.check_bitch_name'));
var dog_names = getInputValues($('.check_dog_name'));
var bitch_promises = checkDogs(bitch_names);
var dog_promises = checkDogs(dog_names);
$.when(bitch_promises, dog_promises).then(function(bitch_errors, dog_errors) {
// update the DOM based on the passed arrays
...
});
});

You are right, ajax calls are like their name says asynchronous. Therefor you can only rely on the .done function. A simple solution would be to initialize a counter variable at the beginning for bitches and dogs and in the according done function you decrement it until it reaches zero. Then, also in the done function, you put an if that calls validation of the error arrays. Here is UNTESTED code to show what I mean:
$('#puppy_form').on('submit', function() {
/*
here you get the initial count for bitches and dogs
*/
var bitch_count = $('.check_bitch_name').length;
var dog_count = $('.check_dog_name').length;
var bitch_errors = [];
var dog_errors = [];
// NOTE: Bitch and dog names need to be checked differently so we know which error is assigned to which input
$('.check_bitch_name').each( function(i, obj) {
// need to check each name for validity and duplication.
var entered_bitch_name = obj.value;
var pattern = /^[a-zA-Z,.]+\s[a-zA-Z,.]+(\s[a-zA-Z,.]+){0,}$/;
if(!pattern.test(entered_bitch_name)) {
bitch_errors[i+1] = "invalid";
} else {
// now to check for duplicates
$.post('/check-puppy-name', { name: entered_bitch_name }
).done(function (response) {
if(response == 'duplicate') {
bitch_errors[i+1] = "duplicate";
} else {
bitch_errors[i+1] = "";
}
/*
now on every checked name you decrement the counter
and if both counters reach zero you can be sure you
checked all and only now you call your validation
*/
bitch_count--;
if(bitch_count === 0 && dog_count === 0) {
return validateErrors();
}
});
}
});
$('.check_dog_name').each( function(i, obj) {
// need to check each name for validity and duplication.
var entered_dog_name = obj.value;
var pattern = /^[a-zA-Z,.]+\s[a-zA-Z,.]+(\s[a-zA-Z,.]+){0,}$/;
if(!pattern.test(entered_dog_name)) {
dog_errors[i+1] = "invalid";
} else {
// now to check for duplicates
$.post('/check-puppy-name', { name: entered_dog_name }
).done(function (response) {
if(response == 'duplicate') {
dog_errors[i+1] = "duplicate";
} else {
dog_errors[i+1] = "";
}
/*
same here
*/
dog_count--;
if(bitch_count === 0 && dog_count === 0) {
return validateErrors();
}
});
}
});
}
/*
...and finally all code that should be processed after the ajax calls
*/
function validateErrors() {
if(count(bitch_errors) == 0 && count(dog_errors) == 0) {
return true;
}
// loop through the errors and assign them to the correct input
$.each( bitch_errors, function( key, value ) {
if (value == "invalid") {
$('input[name="bitch_name['+key+']"]').parent().addClass('has-error');
$('input[name="bitch_name['+key+']"]').next('.error-message').html('Names must be at least two words, and only contain letters');
return false;
} else if(value == "duplicate") {
$('input[name="bitch_name['+key+']"]').parent().addClass('has-error');
$('input[name="bitch_name['+key+']"]').next('.error-message').html('Sorry, this name has already been taken');
return false;
}
});
$.each( dog_errors, function( key, value ) {
if(value != "") {
if (value == "invalid") {
$('input[name="dog_name['+key+']"]').parent().addClass('has-error');
$('input[name="dog_name['+key+']"]').next('.error-message').html('Names must be at least two words, and only contain letters');
return false;
} else if(value == "duplicate") {
$('input[name="dog_name['+key+']"]').parent().addClass('has-error');
$('input[name="dog_name['+key+']"]').next('.error-message').html('Sorry, this name has already been taken');
return false;
}
}
});
return false;
});

You could use the async lib to manage these requests and collect the results which will then be passed into the final callback where you can process them.
I haven't tried to run this code but hopefully it will get you close enough if not already there.
async.parallel({
bitch_errors: function(callback) {
var bitch_errors = [];
async.forEachOf($('.check_bitch_name'), function(obj, i, cb) {
// need to check each name for validity and duplication.
var entered_bitch_name = obj.value;
var pattern = /^[a-zA-Z,.]+\s[a-zA-Z,.]+(\s[a-zA-Z,.]+){0,}$/;
if(!pattern.test(entered_bitch_name)) {
bitch_errors[i+1] = "invalid";
cb();
} else {
// now to check for duplicates
$.post('/check-puppy-name', { name: entered_bitch_name }
).done(function (response) {
if(response == 'duplicate') {
bitch_errors[i+1] = "duplicate";
} else {
bitch_errors[i+1] = "";
}
cb();
});
}
}, function () {
callback(null, bitch_errors);
});
},
dog_errors: function(callback) {
var dog_errors = [];
async.forEachOf($('.check_dog_name'), function(obj, i, cb) {
// need to check each name for validity and duplication.
var entered_dog_name = obj.value;
var pattern = /^[a-zA-Z,.]+\s[a-zA-Z,.]+(\s[a-zA-Z,.]+){0,}$/;
if(!pattern.test(entered_dog_name)) {
dog_errors[i+1] = "invalid";
cb();
} else {
// now to check for duplicates
$.post('/check-puppy-name', { name: entered_dog_name }
).done(function (response) {
if(response == 'duplicate') {
dog_errors[i+1] = "duplicate";
} else {
dog_errors[i+1] = "";
}
cb();
});
}
}, function () {
callback(null, dog_errors);
});
}
}, function(err, results) {
// you can now access your results like so
if(count(results.bitch_errors) == 0 && count(results.dog_errors) == 0) {
// ... rest of your code
});

true == false evaluates to true somehow?

I've been working to scrape some webpage that is using the OWASP CRSFGuard project for protection. The library seems to be causing one of my requests to get a 401 so I started digging through their code and noticed the following;
function isValidDomain(current, target) {
var result = false;
/** check exact or subdomain match **/
if(current == target || current == 'localhost') {
result = true;
} else if(true == false) {
if(target.charAt(0) == '.') {
result = current.endsWith(target);
} else {
result = current.endsWith('.' + target);
}
}
return result;
}
From what I can tell, there must be instances where this code is executed; result = current.endsWith('.' + target);. Given true == false is inherently false, how would the code reach that statement? Is this some JS oddity (I know we're not using the strict === equality, but seriously...)?

Answer: It will never reach that code block.
function isValidDomain(current, target) {
var result = false;
/** check exact or subdomain match **/
if (current == target || current == 'localhost') {
result = true;
} else if (true == false) {
if (target.charAt(0) == '.') {
result = current.endsWith(target);
} else {
result = current.endsWith('.' + target);
}
}
return result;
}
var trueFalse = document.getElementById('trueFalse');
trueFalse.innerHTML = isValidDomain('true', 'false') ? 'WTF!' : 'All is good in the JS World';
trueFalse.addEventListener('click', function(e) {
trueFalse.innerHTML = (true == false) ? 'WTF!' : 'All is good in the JS World Still';
});
<div id="trueFalse"></div>

I would say that Blazemonger is most likely correct.
That else if probably had some other condition at some point, and for whatever reason, they decided they didn't want that block of code to execute anymore, so they changed the condition to something that is always false.
It's also not entirely uncommon to see programmers use 1 === 0 as an indication for false. Why they would want to do this is anybody's guess.

Validation function with return value

I have a common validation function
function connect_and_update_destination() {
var flag = true;
// Validate IP
if (!validate_ip_address()) {
alert(protect.lang.enter_valid_ip);
return;
}
if ($('#pjm_alias').val() === '') {
$('#pjm_alias').focus();
alert(protect.lang.enter_alias);
return;
}
if ($('#pjm_auth_name').val() === '') {
$('#pjm_auth_name').focus();
alert(protect.lang.enter_auth_name);
return;
}
if ($('#pjm_auth_password').val() === '') {
$('#pjm_auth_password').focus();
alert(protect.lang.enter_auth_pwd);
return;
}
var ip = $('#pjm_ip1').val()+'.'+$('#pjm_ip2').val()+'.'+$('#pjm_ip3').val()+'.'+$('#pjm_ip4').val();
return establish_connection(ip, $('#pjm_alias').val(), $('#pjm_auth_name').val(), $('#pjm_auth_password').val());
}
After successful validation it always return establish_connection(), My problem is that am calling this connect_and_update_destination() like this,
function first_call(){
connect_and_update_destination();
}
function second_call(){
connect_and_update_destination();
}
When first call i need to return after successful validation establish_connection(), But when ever i called its using second function [second_call()] it should not return establish_connection() insted of return establish_connection() i need to only return . But how can i do this, Means i dont want to enter establish_connection() when ever i call using second_call().
Thanks in advance.

You could do something as simple as passing a variable.
function connect_and_update_destination(establishConnection) {
...
if(!establishConnection)
return;
return establish_connection(ip, $('#pjm_alias').val(), $('#pjm_auth_name').val(), $('#pjm_auth_password').val());
}
function first_call(){
connect_and_update_destination(true);
}
function second_call(){
connect_and_update_destination(false);
}
For a more generic solution, you could pass a callback:
function connect_and_update_destination(callback) {
...
if(typeof callback === 'function') {
return callback(ip);
}
return;
}
function first_call() {
var result = connect_and_update_destination(function(ip) {
return establish_connection(ip, $('#pjm_alias').val(), $('#pjm_auth_name').val(), $('#pjm_auth_password').val());
});
}
function second_call() {
connect_and_update_destination();
}

You could add a parameter to the connect_and_update_destination function:
function connect_and_update_destination(establishConnection) {
var flag = true;
// Validate IP
if (!validate_ip_address()) {
alert(protect.lang.enter_valid_ip);
return;
}
if ($('#pjm_alias').val() === '') {
$('#pjm_alias').focus();
alert(protect.lang.enter_alias);
return;
}
if ($('#pjm_auth_name').val() === '') {
$('#pjm_auth_name').focus();
alert(protect.lang.enter_auth_name);
return;
}
if ($('#pjm_auth_password').val() === '') {
$('#pjm_auth_password').focus();
alert(protect.lang.enter_auth_pwd);
return;
}
if (!establishConnection) {
return;
}
var ip = $('#pjm_ip1').val()+'.'+$('#pjm_ip2').val()+'.'+$('#pjm_ip3').val()+'.'+$('#pjm_ip4').val();
return establish_connection(ip, $('#pjm_alias').val(), $('#pjm_auth_name').val(), $('#pjm_auth_password').val());
}
and then:
function first_call() {
connect_and_update_destination(true);
}
function second_call() {
connect_and_update_destination(false);
}