Develop Reference

Javascript Serial Number CoderByte problem

I'm currently solving a problem at CoderByte. Here's the scenario.
Have the function SerialNumber(str) take the str parameter being passed and determine if it is a valid serial number with the following constraints:
It needs to contain three sets each with three digits (1 through 9) separated by a period.
The first set of digits must add up to an even number.
The second set of digits must add up to an odd number.
The last digit in each set must be larger than the two previous digits in the same set.
If all the above constraints are met within the string, the your program should return the string true, otherwise your program should return the string false. For example: if str is "224.315.218" then your program should return "true".
Examples
Input: "11.124.667"
Output: false
Input: "114.568.112"
Output: true
Here's my JS code for this problem.
function SerialNumber(str) {
// code goes here
if(str.length < 11) {
return "false";
}
for (let x = 0; x < str.length; x++) {
if(str[x] === '0') {
return "false";
}
}
const first = str[0] + str[1] + str[2];
const second = str[4] + str[5]+ str[6];
if (first % 2 !== 0 || second % 2 === 0) {
return "false";
}
if (str[2] < str[1] || str[2] < str[0] || str[6] < str[5] || str[6] < str[4] || str[10] < str[8] || str[10] < str[9]) {
return "false";
} else {
return "true";
}
}
console.log("11.124.667 : " + SerialNumber("11.124.667"));
console.log("114.568.112 : " + SerialNumber("114.568.112"));
When I input "11.124.667", it will return to false (which is correct). And when I input "114.568.112", it will also return to false (which is not correct). Any tips on how can I obtain this? Thanks for the feedback.

I tried your code and the problem comes from the third return false for the 2nd example, when you set second, you concatenate strings instead of adding numbers, thus %2 is always equal to 0 since
I added console.log before each return false to see which condition failed.
Here's the fixed code in which I added parseInt for first and second
function SerialNumber(str) {
if (str.length < 11) {
console.log("first")
return "false";
}
for (let x = 0; x < str.length; x++) {
if (str[x] === '0') {
console.log("second")
return "false";
}
}
const first = parseInt(str[0]) + parseInt(str[1]) + parseInt(str[2]);
const second = parseInt(str[4]) + parseInt(str[5]) + parseInt(str[6]);
if (first % 2 !== 0 || second % 2 === 0) {
console.log("third")
return "false";
}
if (str[2] < str[1] || str[2] < str[0] || str[6] < str[5] || str[6] < str[4] || str[10] < str[8] || str[10] < str[9]) {
console.log("fourth")
return "false";
} else {
return "true";
}
}
console.log("11.124.667 : " + SerialNumber("11.124.667"));
console.log("114.568.112 : " + SerialNumber("114.568.112"))

Limit numbers before and after decimal point on input number

How to limit numbers for before and after the decimal point, something like 123.123 , so it can have max 3 numbers before . and max 3 numbers after .
<div class="form-group">
<input type="number" class="form-control" name="ta" id="ta" placeholder="ta" ng-model="ta.kol" ng-maxlength="15"/>
<p ng-show="taForm.kol.$error.maxlength" class="help-block">Max 15 symbols !</p>
</div>

You can add a onchange event on the input field and call a function that validates the current input value using regex and communicate same to the user.
Regex : ^[0-9]{0,3}.?[0-9]{0,3}$
JS Code to validate:
function validateNumberInput(inputNumber){
return number.search(/^[0-9]{0,3}.?[0-9]{0,3}$/) == 0 ? true : false;
}
Also you can write a directive in angular that can handle the same.

This can be solved with a simple piece of javascript if you just add an Event Listener to the input and then split the input on the decimal point you can then check the length of both parts and act accordingly.
https://jsfiddle.net/pk07net6/
function checkNumbers()
{
console.log(this.value);
var numbers = this.value.split('.');
var preDecimal = numbers[0];
var postDecimal = numbers[1];
if (preDecimal.length>3 || postDecimal.length>3)
{
alert("Max 3 numbers before and after the decimal point.")
this.select();
}
}
//ADD LISTENER TO INPUT
var input = document.getElementById("numberInput");
console.log(input);
input.addEventListener("change", checkNumbers)

You can use ng-pattern with a regex:
<input ng-pattern="/^[0-9]{1,3}(\.\d{0,3})?/" />
docs: https://docs.angularjs.org/api/ng/directive/ngPattern

For the fraction its pretty easy as you can use Angular number filter. As for the number before the digit you should create a filter like this :
app.filter('beforeDigit', function ($filter) {
return function (input) {
if (input>1000)
return (input % 1000)
elseif(input<1000)
return input;
};
});
So in the end you will end up with something like this :
{{val | filter:{number:3}, filter:beforeDigit }}

After hours of work, I create java-script function which work on keypress event. Number can be 8 characters before decimal separator and 2 character after decimal separator.
https://codepen.io/dumbelovic/pen/bvdXXq
function BeforeAfter(e, obj) {
sepDec = "."
var keycode;
var fieldval = obj.value;
if (window.event) keycode = window.event.keyCode;
else if (e) { keycode = e.which; }
else { return true; }
// denided first charatcter to be zero
if (fieldval == "" && keycode == 48)
return false;
// denided first character to be decimal point
if (fieldval == "" && (keycode == 44 || keycode == 46))
return false;
// enter first decimal point,
// but every next try to eneter decimal point return false
if (fieldval != "" && ((keycode == 44 || keycode == 46))) {
if (fieldval.indexOf(sepDec) < 0) {
var newValue = fieldval + sepDec;
$(obj).val(newValue);
}
return false;
}
var splitfield = fieldval.split(sepDec);
var beforeDecimalPoint;
var afterDecimalPoint;
if (splitfield.length == 1) {
beforeDecimalPoint = splitfield[0];
afterDecimalPoint = "";
}
else if (splitfield.length == 2) {
beforeDecimalPoint = splitfield[0];
afterDecimalPoint = splitfield[1];
}
if (beforeDecimalPoint.length == 8 && keycode != 8 && keycode != 0) {
if (obj.selectionStart >= 0 && obj.selectionStart <= 8)
return false;
}
if (afterDecimalPoint.length == 2 && keycode != 8 && keycode != 0) {
if (obj.selectionStart >= beforeDecimalPoint.length + 1 && obj.selectionStart <= beforeDecimalPoint.length + 1 + 2)
return false;
}
return true;
}

javascript to allow only negative and positive numbers and decimal upto 6 digits on keypress

I need to validate a textbox in my cshtml page to accept only negative or positive numbers and upto 6 decimal places. This is what I have tried so far.
function AcceptUptoSixDecimalPlacesWithNegative(event, elem) {
if ((event.which != 46 || $(elem).val().indexOf('.') != -1) && (event.which < 48 || event.which > 57)) {
if (event.keyCode !== 8 && event.keyCode !== 46 && event.keyCode !== 9 && event.keyCode !== 0 && event.keyCode !== 45) { //exception
event.preventDefault();
}
}
var text = $(elem).val();
if ((text.indexOf('.') != -1) && (text.substring(text.indexOf('.')).length > 6)) {
if (event.keyCode !== 8 && event.keyCode !== 46 && event.keyCode !== 9) { //exception
event.preventDefault();
}
}
This is helping me achieve six digits after decimal point but then it allows all special characters and alphabets too.
Any help with this problem would be appreciated.
Thanks.

You could check the value with Regex:
var re = /^-?\d*\.?\d{0,6}$/;
var text = $(elem).val();
var isValid = (text.match(re) !== null);
The Regex means:
^ : beginning of string
-? : one or zero "-"
\d* : 0 to infinite numbers
\.? : 0 or 1 "."
\d{0,6} : from 0 to 6 numbers
$ : End of string

You could use the isNaN() function of JavaScript.
var inputPrevValue = "";
$(document).ready(function () {
$("#numbersOnly").change(function () {
if (isNaN($(this).val()) || $(this).val().length > 6) {
$(this).val(inputPrevValue);
} else {
inputPrevValue = $(this).val();
}
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
<input type="text" id="numbersOnly">
This is a (very simplistic) example that tests if the input is a number less than 6 characters in length. If not, it'll revert it to the last acceptable value.

***Adding Comment as no access yet!!!
Try Regex "^[0-9]+(.[0-9]{1,2})?$" to verify the text and then proceed with logic.
js code:
var patt = new RegExp("^[0-9]+(.[0-9]{1,6})?$");
var res = patt.test(str);
if res is true then proceed else return false;

Here are a list of functions to help in your question:
Math.sign() checks if its a positive/0, negative/0 and NaN
Number MDN contains a list of number functions
parseFloat()
count digits after decimal post or regex ie. \d+([.\d{1,6}]*)\
In your context, a combination of validations in the following example:
let x = elem;
if(Math.sign(x) === 1 || Math.sign(x) === -1) && ...
// decimal validations
Hope this helps.

Don't validate the keys pressed. There are many ways to change input
value. Handle the oninput event.
You may treat the value as a string and validate using a
regular expression, but I think it's better to combine string and number-related
functions
For example:
<input type="number" step="any" oninput="validate(this)" />
function validate(input){
var number = parseFloat(input.value);
if( number == input.value && input.value.length <= number.toFixed(6).length ){ /* valid! */ }
}
http://jsfiddle.net/tto2yvwj/

IsNan() function considers certain kind of strings as number - node js

I'm checking for integer values in node.js using IsNaN function.
Unexpectedly, this function validates the strings like 1E267146, 1E656716 , 914E6583 to be numbers, as these strings are exponential values. Any way to work around this? In actual scenario i wont get any exponential values.

ECMA6 defines Number.isInteger as follows:
Javascript
function isInteger(nVal) {
return typeof nVal === "number" && isFinite(nVal) && nVal > -9007199254740992 && nVal < 9007199254740992 && Math.floor(nVal) === nVal;
}
but this will also accept scientific notation
console.log(isInteger(1e6));
console.log(isInteger(+"1e6"));
jsfiddle
You need to be clear as to what your definitions/expectations are.
My guess is that you may want something like this, if you are testing strings and have no limits on the max or min integer.
Javascript
function isStringNumericalInteger(testValue) {
return typeof testValue === "string" && /^[\-+]?[1-9]{1}\d+$|^[\-+]?0$/.test(testValue);
}
console.log(isStringNumericalInteger("9007199254740991"));
console.log(isStringNumericalInteger("-123216848516878975616587987846516879844651654847"));
console.log(isStringNumericalInteger("1.1"));
console.log(isStringNumericalInteger("-1.1"));
console.log(isStringNumericalInteger("1e10"));
console.log(isStringNumericalInteger("010"));
console.log(isStringNumericalInteger("0x9"));
console.log(isStringNumericalInteger(""));
console.log(isStringNumericalInteger(" "));
console.log(isStringNumericalInteger());
console.log(isStringNumericalInteger(null));
console.log(isStringNumericalInteger([]));
console.log(isStringNumericalInteger({}));
Output
true
true
false
false
false
false
false
false
false
false
false
false
false
jsfiddle
If you want to bound the range to what javascript can represent numerically as an integer then you will need to add a test for && +testValue > -9007199254740992 && +testValue < 9007199254740992
If you don't like using RegExs, you can also accomplish this with a parser. Something like this:
Javascript
function isCharacterDigit(testCharacter) {
var charCode = testCharacter.charCodeAt(0);
return charCode >= 48 && testCharacter <= 57;
}
function isStringNumericalInteger(testValue) {
var start = 0,
character,
index,
length;
if (typeof testValue !== "string") {
return false;
}
character = testValue.charAt(start);
if (character === "+" || character === "-") {
start += 1;
character = testValue.charAt(start);
}
start += 1;
length = testValue.length;
if ((length > start && character === "0") || !isCharacterDigit(character)) {
return false;
}
for (index = start; index < length; index += 1) {
if (!isCharacterDigit(testValue.charAt(index))) {
return false;
}
}
return true;
}
jsfiddle

I would use something like below code to validate number input. First I parse the given value to float and then check isNaN().
var isNumber = function (obj) {
return !isNaN(parseFloat(obj)) && isFinite(obj);
};

I think this is what you need in your case (i hate regex because this is not very good for the performance but..)
http://jsbin.com/EQiBada/1/
var NMAX = Math.pow(2, 53);
function isNumeric(n) {
n = n < 0 ? n * -1 : n;
var r = /^\d+$/.test(n);
if (r === true)
{
return parseInt(n, 10) >= (NMAX * -1) + 1 && parseInt(n, 10) <= NMAX;
}
return false;
}
Minified
var NMAX = Math.pow(2, 53);
function isNumericMin(n) {
n = n < 0 ? n * -1 : n;
return /^\d+$/.test(n) === true ? parseInt(n, 10) >= (NMAX * -1) + 1 && parseInt(n, 10) <= NMAX : false;
}

var i = '1E267146'
if(isNaN(i) || !isFinite(i) !! i=="")
{
// do stuff
}
else
{
// do stuff
}

regex for javascript pattern match

i'm looking for a regex expression or javascript which alerts me when a number is NOT between 48-47 or NOT between 96-105 or IS NOT 110 OR 190 OR 8 OR 13.
thanks for all the help friends !!

Regex is not appropriate for such specific numeric checks. Just do a few if statements to compare the value you're working with to the specific values and ranges you want to exclude.
var number = 19;
alert('Number is'+(numberIsValid(number) ? 'valid' : 'not valid'));
function numberIsValid(number) {
// test for numeric argument
if ((number - 0) != number)
return false;
// test for specific exclusions
if (number == 110 || number == 190 || number == 8 || number == 13 || number == 48 || number == 47)
return false;
// test for excluded range
if (number >= 96 && number <= 105)
return false;
return true;
}

I agree with Chris's response above, if you want to see what it would look like, it is kind of a mess. I wouldn't really recommend you use this.
Just to rephrase: Number may not be 8,13,47,48,96-105,110
var num = 10;
if (! /^(8|13|47|48|9[6-9]|10[0-5]|110)$/.test(num)) {
alert(num);
}

function allowedIntegers(n){
return !/^([^\d]|8|13|47|48|110|190|96|97|98|99|100|101|102|103|104)$/.test(String(n));
}