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check that a word is an isogram with pure javascript

How do i check that a given word is an isogram with pure javascript, using a function. the function must return true or false.
An isogram is a word with a repeated character.
I know this code works, but i need a better solution.
function isIsogram(word){
x = false; y = false;
for(i = 0; i < word.length; i++){
wordl = word.substring(0,i)
wordr = word.substring(i)
x = wordl.includes(word.charAt(i))
y = wordr.includes(word.charAt(i))
//console.log(x,wordl,wordr)
}
return x&&y
}
isIsogram("thomas");//False
isIsogram("moses"); //True

Remove the duplicate letter from string then check both length. if same its an isogram.
function isIsogram(str){
return str.split('').filter((item, pos, arr)=> arr.indexOf(item) == pos).length == str.length;
}
console.log(isIsogram('thomas'));
console.log(isIsogram('moses'));

One way of doing this!
function isIsogram(str){
return !str.match(/([a-z]).*\1/i);
}

Here is a simple approach using .split() and .every():
let isIsogram = (str) => str.split("").every((c, i) => str.indexOf(c) == i);
console.log(isIsogram("thomas")); /* no repeating letter */
console.log(isIsogram("moses")); /* s repeat 2 times */
console.log(isIsogram("hello")); /* l repeat 2 times */
console.log(isIsogram("world")); /* no repeating letter */
console.log(isIsogram("a b c")); /* space character repeat 2 times */
Docs:
String.prototype.split()
String.prototype.indexOf()
Array.prototype.every()

Building on kishea's answer:
function isIsogram(sWord)
{
for (iCharIndex = 0; iCharIndex < sWord.length; iCharIndex++)
if (sWord.substring(iCharIndex + 1).includes(sWord.charAt(iCharIndex)))
return false;
return true;
}
If the character at the current position (charAt) is found (includes) to the right of the current position (substring), false is returned. Otherwise the loop runs to the end and true is returned.

const isIsogram = (word) => {
return new Set(word.toLowerCase()).size === word.length
}
console.log(isIsogram('Thor'));//true
console.log(isIsogram('Loki'));//true
console.log(isIsogram('America'));//false

function isIsogram(str) {
return new Set(str.toUpperCase()).size == str.length
}

What about :
> function isIsogram(word) {
... var a = word.split('')
... var b = Array.from(new Set(a))
... return a.length === b.length;
... }
undefined
> isIsogram("mesos")
false
> isIsogram("thomas")
true
Or better (checking each char only once) :
> function isIsogram2(word) {
... for(var i=0,len=word.length-1;i<len;++i) {
..... var c = word[i]
..... if(word.indexOf(c,i+1) !== -1) return false;
..... }
... return true;
... }
undefined
> isIsogram2("mesos")
false
> isIsogram2("thomas")
true

function isIsogram(word){
return !/(.).*\1|\d/i.test(word)
}

var str=prompt('Enter a string');
var strlen=str.length;
for(i=0;i<strlen;i++){
var stc=str.charAt(i);
var flag=0;
for(j=0;j<strlen;j++){
var stk=str.charAt(j);
if(stc==stk){
flag=flag+1;
}
}
if(flag!=1){
break;
}
}
if(flag!=1){
alert('It is not an isogram');
}
else{
alert('It is an isogram');
}

While given a word, this function if splits the word into two,
That is wordl and wordr respectively.
Both splittings are checked to include a character in the original word. If wordl and wordr both contain any character in the original word. Then surely this is an isogram
function isIsogram(word){
x = false; y = false;
for(i = 0; i < word.length; i++){
wordl = word.substring(0,i)
wordr = word.substring(i)
x = wordl.includes(word.charAt(i))
y = wordr.includes(word.charAt(i))
//console.log(x,wordl,wordr)
}
return !x&&y
}
isIsogram("thomas");//True
isIsogram("moses"); //False

const isIsogram = (string) => {
const lowerCased = string.toLowerCase()
const result = lowerCased.split('').every((v,i)=>lowerCased.indexOf(v)===i)
return result
}
console.log(isIsogram('ambidExtRously')) // true
console.log(isIsogram('patteRN')) // false

function isIsogram(word) {
let uniqueCharacters = new Set(word.split(''));
uniqueCharacters = Array.from(uniqueCharacters); //get all the unique char
let charFreq = {}; //e.g {a:2, b:3}
for (element of uniqueCharacters) {
charFreq[element] = 0;
} //set the frequency of each char to zero
function updateFrequency(element) {
charFreq[element] += 1;
}//callback used directly below
word.split('').forEach(updateFrequency); //for each char encountered, update frequency
let frequencyOfCharacter = [];
for (keys in charFreq) {
frequencyOfCharacter.push(charFreq[keys]);
}
function equal(item) {
return item === frequencyOfCharacter[0];
}
//check if all the frequencies are the same, an isogram means all characters occur at the same frequency
return frequencyOfCharacter.every(equal);
}
console.log(isIsogram('try'), isIsogram('baba'), isIsogram('tests'));

javascript for loop is not incrementing

I am trying to using a for loop for trying to validate the input of the user and this is the code i got.
function Valid() {
objfieldid = ["userMail", "userCont"]
objboxid = ["cancelMail", "cancelCont"]
return objfieldid.every(callnonvalid)
}
function callnonvalid(id) {
var valid = false
var objlength = objfieldid.length
objlength--;
for (var i = objlength; i >= 0; i--){
var cobj = document.getElementById(objboxid[i]).checked;
if (document.getElementById(id).value != "" ){
var obj = document.getElementById(id).value;
} else if (cobj == true) {
alert(i); //return 1, 1
return true
} else {
return false
}
}
}
As you can see, in the code, the for loop is running twice. but the i variable is left unchanged. Why would this happen?
btw, I did read different material about closure and i am sure there didnt got a closure problem
EDIT:guys please note that i did noticed the array is zero based, and i did minus the objlength by one.

Mistakes were found after checking the code carefully. The Mistake that I made was that I should not use the return for the out since that would stop the function from working, however that array.every Called the function twice which make the i not decreasing

I'm not sure why you're decrementing in your loop, because the performance gain would be infinitesimally small (it may even be slower, e.g. in Chrome/V8) and working in reverse order can get confusing further down the line, but that's your choice and I don't know enough about what you're doing to judge.
Either way, I don't think you'd want to decrement objlength before the loop begins as you are doing now. The whole point of a loop is to handle the incrementing/decrementing in the condition statement of the loop.
You would only decrement manually like that if you were going to move your if/else if/else statement into a closed over function and execute it recursively, decrementing the objlength from within the closure. Which would work, but it's unnecessarily complicated for what you're doing and you would gain nothing for rewriting the whole thing.
So, sticking with the looping approach, perhaps try either of these:
function Valid() {
objfieldid = ["userMail", "userCont"];
objboxid = ["cancelMail", "cancelCont"];
return objfieldid.every(callnonvalid);
}
function callnonvalid(id) {
var valid = false;
var objlength = objfieldid.length;
for(var i = 0; i < objlength; i++){
var cobj = document.getElementById(objboxid[i]).checked;
if (document.getElementById(id).value != "" ){
var obj = document.getElementById(id).value;
} else if (cobj == true) {
alert(i);
return true;
} else {
return false;
}
}
}
or, if you want to decrement, use while instead of for:
function Valid() {
objfieldid = ["userMail", "userCont"];
objboxid = ["cancelMail", "cancelCont"];
return objfieldid.every(callnonvalid);
}
function callnonvalid(id) {
var valid = false;
var i = objfieldid.length;
while(i--){
var cobj = document.getElementById(objboxid[i]).checked;
if (document.getElementById(id).value != "" ){
var obj = document.getElementById(id).value;
} else if (cobj == true) {
alert(i);
return true;
} else {
return false;
}
}
}

Because the array objboxid[] has only two elements, the first time through your loop objboxid[2] will be attempting to fetch an array index that is out-of-bounds.
You probably meant something like:
for (var i = objlength; i > 0; i--){
var cobj = document.getElementById(objboxid[i-1]).checked;
or perhaps
for (var i = objlength-1; i >= 0; i--){
var cobj = document.getElementById(objboxid[i]).checked;

Javascript object members

var math = {
Factorial:function(n) {
if (n == 0) {
return 1;
}
return n * Factorial(n - 1);
},
CalculateFactorial:function() {
var myValue = document.getElementById('myTextBox').value;
if (myValue.length == 0) {
alert("Please input the correct value!");
return;
}
var result = Factorial(myValue);
document.getElementById('title').innerHTML = result;
}
}
Hello guys. New to JavaScript and testing different things, coming from C# language things are pretty the same yet different.
I am trying to do something and no success.
Having the script above attached to a simple html button , trying to call the CalculateFactorial , math.CalculateFactorial(); , but what is wierd is that CalculateFactorial() doesn't actually see the Factorial() method. But in the math object I can see both methods. Wierd.
"JavaScript runtime error: 'Factorial' is undefined"

A good practice in JavaScript is to name all of your functions even if you assign them to a variable or use them like object's property. In your case just give a name to your Factorial function like this:
Factorial:function factorial(n)
{
if (n == 0)
{
return 1;
}
return n * factorial(n - 1);
},
For the problem of not seeing Factorial in your CalculateFactorial function just use this.Factorial when you invoke it.

This should fix the issue... if you want Factorial to be an internal only function (just a utility for the exposed CalculateFactorial) then you can do so this way:
var math = new function() {
var $this = this;
var Factorial = function(n) {
if (n == 0) {
return 1;
}
return n * Factorial(n - 1);
}
$this.CalculateFactorial = function() {
var myValue = document.getElementById('myTextBox').value;
if (myValue.length == 0) {
alert("Please input the correct value!");
return;
}
var result = Factorial(myValue);
document.getElementById('title').innerHTML = result;
}
}
The deeper design issue here is this is not particularly reusable javascript. You should consider pulling CalculateFactorial() out of the math object and into it's own handler... probably a click handler would be my guess like this:
var math = new function() {
var $this = this;
$this.Factorial = function(n) {
if (n == 0) {
return 1;
}
return n * $this.Factorial(n - 1);
}
}
$("#calcButton").click(function() {
var myValue = document.getElementById('myTextBox').value;
if (myValue.length == 0) {
alert("Please input the correct value!");
return;
}
var result = math.Factorial(myValue);
document.getElementById('title').innerHTML = result;
})

That happens beceause the Factorial method is part of the math object, and it doesn't reside in the global scope. When you try to call it directly, the parser will try to find that method into the global scope, and then, it will thrown an ReferenceError.
Since you're using the method inside the object itself, you can use the this keyword, because it will look into the object's context and find the method Factorial.
Another way of calling the Factorial method is by using the object, e.g: math.Factorial.
Take a look at the example below:
var math = {
Factorial: function(n) {
return n === 0 ? 1 : n * this.Factorial(n - 1);
},
CalculateFactorial: function(txt) {
document.getElementById('title').innerHTML = this.Factorial(txt.value);
}
};
document.getElementById('myTextBox').addEventListener('input', function() { math.CalculateFactorial(this); });
<input type="text" id="myTextBox" placeholder="Fatorial">
<div id="title"></div>

Check for continuous order in array in javascript

var userInput = prompt('enter number here');
var number = new Array(userInput.toString().split(''));
if (number ????){ //checks if the number is in a continuous stream
alert(correct);
}
else{
alert(invalid);
}
In Javascript, what can I do at "????" to check if it is in a continuous order/stream? Also how can I do this so that it only checks for this order/stream after a specific index in the array? Meaning the user enters say "12345678901234" which would pop up correct, but "12347678901234" would pop up invalid?(note there are two 7's) For the second part "3312345678901234" would pop up correct, how can this be implemented?

You can make a function that checks any string for a stream of continuous/increasing alpha-numeric characters starting at a given index like this:
function checkContinuous(str, startIndex) {
startindex = startIndex || 0;
if (str.length <= startIndex) {
return false;
}
var last = str.charCodeAt(startIndex);
for (var i = startIndex + 1; i < str.length; i++) {
++last;
if (str.charCodeAt(i) !== last) {
return false;
}
}
return true;
}
If it's numbers only and wrapping from 9 back to 0 is considered continuous, then it's a little more complicated like this:
function checkContinuous(str, startIndex) {
// make sure startIndex is set to zero if not passed in
startIndex = startIndex || 0;
// skip chars before startIndex
str = str.substr(startIndex);
// string must be at least 2 chars long and must be all numbers
if (str.length < 2 || !/^\d+$/.test(str)) {
return false;
}
// get first char code in string
var last = str.charCodeAt(0);
// for the rest of the string, compare to last code
for (var i = 1; i < str.length; i++) {
// increment last charCode so we can compare to sequence
if (last === 57) {
// if 9, wrap back to 0
last = 48;
} else {
// else just increment
++last;
}
// if we find one char out of sequence, then it's not continuous so return false
if (str.charCodeAt(i) !== last) {
return false;
}
}
// everything was continuous
return true;
}
Working demo: http://jsfiddle.net/jfriend00/rHH4B/

No need for arrays, just back though the string one character at a time.
When you hit a 0, substitute 10, and continue until the number
is not one more than the previous one.
function continuousFromChar(str, start){
start= start || 0;
var i= 0, L= str.length, prev;
while(L){
c= +(str.charAt(-- L)) || 10; // use 10 for 0
prev=+(str.charAt(L- 1));
if(c-prev !== 1) break;
}
return start>=L;
}
var s= "3312345678901234";
continuousFromChar(s,2)
/* returned value: (Boolean)
true
*/

This will do the checking in real-time entry, but a similar principle could be used to check an entry on a button submit or similar. I was not 100% sure as to which way you wanted it, so I went for the live method.
HTML
<input id="stream" type="text" />
Javascript
window.addEventListener("load", function () {
document.getElementById("stream").addEventListener("keyup", function (evt) {
var target = evt.target;
var value = target.value;
var prev;
var last;
var expect;
target.value = value.replace(/[^\d]/, "");
if (value.length > 1) {
prev = parseInt(value.slice(-2, -1), 10);
last = parseInt(value.slice(-1), 10);
expect = prev + 1;
if (expect > 9) {
expect = 0;
}
if (last !== expect) {
target.value = value.slice(0, value.length - 1);
}
}
}, false);
});
On jsfiddle
By changing the value here
if (value.length > 1) {
You can change where the checking starts.
Update: Ok, so it is function that you want, and you insist that it splits the string into an array. Then using the above as a reference, you could convert it to something like this.
Javascript
window.addEventListener("load", function () {
var testStrings = [
"0123456789012",
"0123456789",
"0123455555",
"555012345678901234",
"0123455555"];
function test(string, offset) {
if (typeof string !== "string" || /[^\d]/.test(string)) {
return false;
}
var array = string.split("");
var prev;
var last;
var expect;
return !array.some(function (digit, index) {
if (index >= offset) {
prev = parseInt(array[index - 1], 10);
last = parseInt(digit, 10);
expect = prev + 1;
if (expect > 9) {
expect = 0;
}
if (last !== expect) {
return true;
}
}
return false;
});
}
testStrings.forEach(function (string) {
console.log(string, test(string, 1));
});
});
On jsfiddle
As your question does not fully specify all possibilities, the above will return true for an empty string (""), of course you can simply add a check at the very beginning for that.
I also do not perform any checking for a valid number for your offset, but again this is something simple that you can add.
Of course these are just one (two) of many possible solutions, but hopefully it will set your mind in the right direction of thought.

There are some good answers here, but I would like to show a slight variation. I think it is important to showcase some different aspects of JavaScript and separating interests in code.
Functions as first class objects are cool - the exact rules for "continuous" can be changed with only changing the predicate function. Perhaps we should allow skipping numbers? No problem. Perhaps we allow hex digits? No problem. Just change the appropriate follows function for the specific rules.
This can be implemented generically because strings support indexing. This will work just as well over other array-like objects with an appropriate follows function. Note that there are no string-specific functions used in the continuous function.
Code also on jsfiddle:
// returns true only iff b "follows" a; this can be changed
function follows_1Through9WithWrappingTo0(b,a) {
if (b === "1" && a === undefined) {
// start of sequence
return true;
} else if (b === "0" && a === "9") {
// wrap
return true;
} else {
// or whatever
return (+b) === (+a) + 1;
}
}
function continuous(seq, accordingTo, from) {
// strings can be treated like arrays; this code really doesn't care
// and could work with arbitrary array-like objects
var i = from || 0;
if ((seq.length - i) < 1) {
return true;
}
var a = undefined;
var b = undefined;
for (; i < seq.length; i++) {
b = seq[i];
if (!accordingTo(b, a)) {
return false; // not continuous
}
a = b;
}
return true;
}
function assert(label, expr, value) {
if (!(expr === value)) {
alert("FAILED: " + label);
}
}
var follows = follows_1Through9WithWrappingTo0;
assert("empty1", continuous("", follows), true);
assert("empty2", continuous("foobar", follows, 6), true);
assert("skip", continuous("331234", follows, 2), true);
assert("good 1", continuous("123456789", follows), true);
assert("good 2", continuous("12345678901234", follows), true);
assert("bad seq 1", continuous("12347678901234", follows), false);
assert("bad seq 2", continuous("10", follows), false);
// here a different predicate ensures all the elements are the same
var areAllSame = function (b, a) {
return a === undefined || a === b;
};
assert("same", continuous("aaaaa", areAllSame), true);
Note that the skipping could also be extracted out of the continuous function: in a language with better "functional" collection support, such as C#, this is exactly what I'd do first.

Can't iterate array returned from Sizzle

From my understanding Sizzle returns an array of objects (DOMElements), I am trying to walk that array of objects in a for loop but I am getting errors. When I try to get a property with the
obj[index-number]["property"]
it works fine, but when I try to access it after passing it to another function
obj[index-number][arguments[index-number]]
I am getting a return of undefined. I have tried many different ways, including eval to parse the dot notation to no avail. I am stumped. Any pointers or ideas would be awesome. Also, I have verified all input to the function is correct (through alerting them out), also, hard coding the values to get what I want in the function works as well. Here is my code: (sorry it's lengthy).....
var ecmafw = function() {
// Creates the new instance of the object.
// Sets up the objects global properties:
this.error = false;
// Checks to see if arguments were supplied, if none are then it returns false.
if (arguments.lenght == 0) {
this.error = "No arguments were supplied.";
return false;
}
// Gives a reference to the result set.
this.results = Sizzle(arguments[0]);
this.attr = function() {
/* Purpose: To add/remove/update an attribute from the results set.
*
* Can be used in two ways:
* 1: .attr("attribute1='value' attribute2='value' attribute3='value'") // adds/removes them all. [negate value to be removed with "-" (used for class)]
* 2: .attr("attribute", "value") // adds the one. [negate value to be removed with "-" (used for class)]
* 3: .attr("attribute") // removes the one.
* 4: .attr("attribute1 attribute2 attribute3") // removes them all.
*/
var len = this.results.length;
switch (arguments.length) {
case 1:
for (var a=0; a < len; a++) {
var re = new RegExp("=", "g");
if (re.test(arguments[0])) {
// Provided a list of attributes to update/create.
valuePairs = arguments[0].split("' ");
for (var i=0; i < valuePairs.length; i++) {
var attributeValue = valuePairs[i].split("=");
var newRE = new RegExp(/^-/);
var value = attributeValue[1].replace(/'/g, "");
if (newRE.test(value)) {
this.removeAttr(attributeValue[0], a, value);
} else {
this.setAttr(attributeValue[0], value, a);
}
}
} else {
var attributeSplit = arguments[0].split(" ");
if (attributeSplit.length == 1) {
// Provided a single attributes to remove.
this.removeAttr(arguments[0], a);
} else {
// Provided multiple attributes to remove.
for (var i=0; i < attributeSplit.length; i++) {
this.removeAttr(attributeSplit[i], a);
}
}
}
}
break;
case 2:
// Provided a single name/value pair to update.
for (var a=0; a < len; a++) {
this.setAttr(arguments[0], arguments[1], a)
}
break;
default:
// Either 0 or more than 2 arguments were supplied.
this.error = "There were no arguments supplied with the attr() function, or there were too many supplied.";
return false
break;
}
};
this.setAttr = function() {
// Counters for IE className
if (document.all && !window.opera) {
arguments[0] = arguments[0].replace(/class/gi, "className");
}
if (arguments[0] == "class" || arguments[0] == "className") {
if (this.results[arguments[2]][arguments[0]] != undefined) {
arguments[1] += " " + this.results[arguments[2]][arguments[0]]; // Failing
}
}
if (this.results[arguments[2]].setAttribute) {
this.results[arguments[2]].setAttribute(arguments[0], arguments[1]);
} else {
this.results[arguments[2]][arguments[0]] = arguments[1];
}
};
this.removeAttr = function() {
arguments[0] = arguments[0].replace(/class/gi, "className");
var item = this.results[arguments[1]];
if (arguments[0] == "className") {
arguments[2] = arguments[2].replace("-", "");
var replaceRE = new RegExp(arguments[2], "gi");
// For some reason it would find it like this, This is fine but it is not working
// in Opera. Opera is failing to convert item[eachItem] to an object. (so it says in its error log)
for (var eachItem in item) {
if (arguments[0] == eachItem) {
item[eachItem] = item[eachItem].replace(replaceRE, " ");
item[eachItem] = item[eachItem].replace(/ /gi, " ");
item[eachItem] = item[eachItem].replace(/^ /gi, "");
item[eachItem] = item[eachItem].replace(/ $/gi, "");
}
}
} else {
if (this.results[arguments[1]].removeAttribute) {
this.results[arguments[1]].removeAttribute(arguments[0]);
} else {
this.results[arguments[1]][arguments[0]] = "";
}
}
};
// Returns a reference to itself.
return this;
}

Not sure if this might be the problem, but in the removeAttr function you are accessing the 3rd argument passed in on this line:
arguments[2] = arguments[2].replace("-", "");
However, in 2 of the 3 calls to this function you only pass in 2 arguments. If the above line runs in either of those cases arguments[2] would be undefined and calling replace("-", "") on it would throw an error.
Also, you have a typo in your initial arguments check near the top: arguments.lenght.