I want to do something that can be passed through a function immediately after a value
for example:
// my value
let str = "example";
// my func
let sum = value => {
if(value.length + 1 == 7) { return true; }
else{ return false; }
}
// I want it to work when I write it like this.
console.log( "awesome".sum() )
// I want it to work when I write it like this.
You need to add the method to String.prototype
String.prototype.sum = function()
{
return this.length + 1 == 7;
};
Or simply
String.prototype.sum = function()
{
return this.length === 6;
};
Add the function in String.prototype
String.prototype.sum = function(){
if(this.length + 1 == 7) { return true; }
else{ return false; }
}
console.log( "awesome".sum() )
console.log( "awesom".sum() )
You have to extend the String class.
Standard
let str = "example";
String.prototype.sum = value => {
if(value.length + 1 == 7) { return true; }
else{ return false; }
}
console.log( "awesome".sum(3) )
ES6
Object.assign(String.prototype, {
sum (value) {
if(value.length + 1 == 7) { return true; }
else{ return false; }
}
});
Related
I'm a beginner in JS and trying to sort some cars by their model. The models are sorted by ranking in this order (Mercedes, BMW, Jeep, Nissan). I would like it to be case-insensitive. I went about it by creating a variable for creating the desired rankings.
var modelRanking = function(car) {
if (car.model.toLowerCase() === 'mercedes') {
return 1;
} else if (car.model.toLowerCase() === 'bmw') {
return 2;
} else if (car.model.toLowerCase() === 'jeep') {
return 3;
} else if (car.model.toLowerCase() === 'nissan') {
return 4;
} else {
return 5;
}
}
function modelComparator(car1, car2) {
if (car1.modelRanking < car2.modelRanking) {
return true;
} else if (car1.modelRanking > car2.modelRanking) {
return false;
} else if (car1.modelRanking == car2.modelRanking) {
return yearComparator(car1, car2);
}
}
However the modelRanking is always returning 5.
Instead of car1.modelRanking, use modelRanking(car1) because modelRanking is a function in global scope, not a property of car1.
function modelComparator(car1, car2) {
if (modelRanking(car1) < modelRanking(car2)) {
return true;
} else if (modelRanking(car1) > modelRanking(car2)) {
return false;
} else if (modelRanking(car1) == modelRanking(car2)) {
return yearComparator(car1, car2);
}
}
I want to create a function that is able to determine if a number is same or palindrome. if a given number is palindrome or same then return 2 otherwise if it is not palindrome or same then i need check it twice by increment the given number by 1. after that if it palindrome or same then return 1. if no palindrome or same number found then return 0. i write the function which is giving me the exact result when i give the number as 11211 but the function don't show any response if i enter 1122 or other random value. please help me to find where the error of my function.
function sameOrPalindrome(num) {
var c = 0;
var al = 0;
var normalArray = num.toString().split("");
var revArray = num.toString().split("").reverse();
for (var i = 0; i < normalArray.length; i++) {
if (normalArray[i] != revArray[i]) {
c++;
}
}
if (c == 0) {
return 2;
} else {
num++;
al = sameOrPalindrome(num);
if (al == 2) {
return 1;
} else {
num++;
al = sameOrPalindrome(num);
if (al == 2) {
return 1;
}
}
}
return 0;
}
console.log("1233",sameOrPalindrome(1233))
here is my solution to this problem:
function reversedNum(num) {
return (
parseFloat(
num
.toString()
.split('')
.reverse()
.join('')
) * Math.sign(num)
)
}
function sameOrPalindrome(num) {
if (num === reversedNum(num)) {
return 2;
} else {
num++;
if (num === reversedNum(num)) {
return 1;
} else {
num++;
if (num === reversedNum(num)) {
return 1;
}
}
}
return 0;
}
console.log("1233",sameOrPalindrome(1233))
Perhaps not using recurse - I think your function loops
const allEqual = arr => arr.every( v => v === arr[0] )
const sameOrPalin = num => {
const str = String(num);
let arr = str.split("")
if (allEqual(arr)) return 2
arr.reverse();
if (arr.join("") === str) return 1;
return 0
};
console.log("1111",sameOrPalin(1111));
console.log("2111",sameOrPalin(2111));
console.log("2112",sameOrPalin(2112));
console.log("1234",sameOrPalin(1234));
for (let i = 2111; i<=2113; i++) console.log(i,sameOrPalin(i));
Question: I assumed if palindrome test is true at first time then return 2. if not try incrementing by one and test the palindrome again . if true return 1 else try incrementing for last time and check the palindrome if true return 1 else 0.
Store string into array first and do arr.reverse().join("") to compare
let arr=num.toString().split("");
if(num.toString() == arr.reverse().join(""))
function sameOrPalindrome(num, times) {
let arr = num.toString().split("");
if (num.toString() == arr.reverse().join("")) {
if (times == 3) return 2
else return 1;
} else if (times > 0) {
num++; times--;
return sameOrPalindrome(num, times);
} else return 0
}
console.log(sameOrPalindrome(123321, 3));
console.log(sameOrPalindrome(223321, 3));
console.log(sameOrPalindrome(323321, 3));
Your function needs to know if it should not call itself any more, e.g. when it's doing the second and third checks:
function sameOrPalindrome(num,stop) { // <-- added "stop"
var c = 0;
var al = 0;
var normalArray = num.toString().split("");
var revArray = num.toString().split("").reverse();
for (var i = 0; i < normalArray.length; i++) {
if (normalArray[i] != revArray[i]) {
c++;
}
}
if (c == 0) {
return 2;
} else if(!stop) { // <-- check of "stop"
num++;
al = sameOrPalindrome(num,true); // <-- passing true here
if (al == 2) {
return 1;
} else {
num++;
al = sameOrPalindrome(num,true); // <-- and also here
if (al == 2) {
return 1;
}
}
}
return 0;
}
for(let i=8225;i<8230;i++)
console.log(i,sameOrPalindrome(i));
function check_palindrom(num){
var c1 = 0;
var normalArray = num.toString().split("");
var revArray = num.toString().split("").reverse();
for (var i = 0; i < normalArray.length; i++) {
if (normalArray[i] == revArray[i]) {
c1++;
}
}
if(c1==0){
return 2;
}else{
return 1;
}
}//check_palindrom
function my_fun_check_palindrome(mynum){
//console.log(mynum);
var num = mynum;
var c2 = 0;
var al = 0;
var normalArray = mynum.toString().split("");
var revArray = mynum.toString().split("").reverse();
for (var j = 0; j < normalArray.length; j++) {
if (normalArray[j] == revArray[j]) {
c2++;
}
}
if(c2==0){
console.log('Number is palindrome. Return Value :'+ 2);
}
if(1){
console.log('checking again with incremeting value my one');
num = parseInt(num)+1;
al = check_palindrom(num);
if(al==2){
console.log('Number is palindrome. Return Value :'+ 1);
}else{
console.log('Number is not palindrome. Return Value :'+ 0);
}
}
}//my_fun_check_palindrome
console.log(my_fun_check_palindrome(1122));
console.log(my_fun_check_palindrome(11221));
We should always strive to make function more effiecient... you dont need to run full loop. plus actual checking of palindrome can me modularized
function isSameOrPalindrome(num) {
var normalArray = num.toString().split("");
var revArray = num.toString().split("").reverse(),
i;
for (i = 0; i < normalArray.length / 2; i++) {
if (normalArray[i] !== revArray[i]) {
break;
}
}
if (i >= normalArray.length/2) {
return "Palindrome";
} else {
return "Not Palindrome";
}
}
function doCheck(num) {
var isPalindrome = isSameOrPalindrome(num);
console.log(isPalindrome);
if(isPalindrome === "Palindrome") {
return 2;
} else {
num++;
isPalindrome = isSameOrPalindrome(num);
if(isPalindrome === "Palindrome") {
return 1;
} else {
return 0
}
}
}
console.log("100",doCheck(100));
I have the next function:
function solveSudoku(prev_tab, fila, columna) {
let tab = _.cloneDeep(prev_tab);
let sig_fila = fila;
let sig_col = columna;
if (fila === 8 && columna === 8) {
//console.log(tab);
return tab;
}
if (columna === 8) {
sig_col = 0;
sig_fila = sig_fila + 1
} else {
sig_col = sig_col + 1;
}
if ((tab[fila][columna]) !== '') {
solveSudoku(tab, sig_fila, sig_col)
} else {
for (let num = 1; num <= 9; num++) {
if (numeroValido(tab, num, fila, columna)) {
tab[fila][columna] = num;
//tab.toString();
solveSudoku(tab, sig_fila, sig_col)
}
}
}
}
it returns undefined instead of a 2D array, i already try to add return in every recursive call =>
return solveSudoku( tab, sig_fila, sig_col )
but now that doesn't work either
I'm not really familiar with algorithms for solving sudoku, so I don't know if the algorithm below is correct.
But you need to ensure that the result of the recursion is returned. In my update below, I return the first recursive call. In the loop, I only return it if the recursion successfully found a solution, otherwise the loop continues trying other numbers in the column.
function solveSudoku(prev_tab, fila, columna) {
let tab = _.cloneDeep(prev_tab);
let sig_fila = fila;
let sig_col = columna;
if (fila === 8 && columna === 8) {
//console.log(tab);
return tab;
}
if (columna === 8) {
sig_col = 0;
sig_fila = sig_fila + 1
} else {
sig_col = sig_col + 1;
}
if ((tab[fila][columna]) !== '') {
return solveSudoku(tab, sig_fila, sig_col)
} else {
for (let num = 1; num <= 9; num++) {
if (numeroValido(tab, num, fila, columna)) {
tab[fila][columna] = num;
//tab.toString();
let result = solveSudoku(tab, sig_fila, sig_col);
if (result) { // continue searching if the recursion failed
return result;
}
}
}
}
}
I have a section of code where a variable contains a particular string (here it's multiply), and when I check if the variable has that particular string, the condition always equates to false. I cannot find what I'm missing here.
// calculations
$scope.$watch('colInput.' + el.key, function () {
angular.forEach($scope.colInput[el.key], function (item, index) {
angular.forEach($scope.column[el.key], function (item_1, index_1) {
if (item.hasOwnProperty(item_1.key)) {
item[item_1.key].type = item_1.type;
item[item_1.key].id = item_1.id;
item[item_1.key].options = item_1.options;
}
else {
item[item_1.key] = {};
item[item_1.key].type = item_1.type;
item[item_1.key].id = item_1.id;
item[item_1.key].options = item_1.options;
}
})
angular.forEach(item, function (elem, key) { //each column of the row
var operand_1, operator, operand_2;
if (elem.type == 10) {
// analyzing the formula
elem.options.forEach(function (el, index) {
if (isNaN(el) && index == 1) {
operator = el;
} else if (isNaN(el) && index == 0) {
operand_1 = el;
} else if (isNaN(el) && index == 2) {
operand_2 = el;
} else if (!isNaN(el)) {
operand_2 = parseFloat(el);
}
})
console.log(operator, eval(operator === "multiply"), typeof operator);
if (operator == 'multiply') {
console.log("IF---")
elem.value = parseFloat(item[operand_1].value) * operand_2;
}
}
})
})
}, true)
It looks like your operator is an HTML element not a String.
The comparison with multiply will always be false.
I have a form with a validation script that works perfectly. I would however like the form to jump to the fields that doesn't validate or display the name of the fields in the error message.
The code I use to validate is:
else
{
var valid = document.formvalidator.isValid(f);
}
if (flag == 0 || valid == true) {
f.check.value = '<?php echo JUtility::getToken(); ?>';//send token
}
else {
alert('There was an error with the fields..');
return false;
}
return true;
How can I get the alert to name the fields that need to be filled in correctly or jump to the specific field?
Edited ----------
Hi,
Thanks for help so far. I'm very new to JS. The form is in a component of Joomla.
The full function that validates the form is
function validateForm(f){
var browser = navigator.appName;
if (browser == "Microsoft Internet Explorer"){
var flag = 0;
for (var i=0;i < f.elements.length; i++) {
el = f.elements[i];
if ($(el).hasClass('required')) {
var idz= $(el).getProperty('id');
if(document.getElementById(idz)){
if (!document.getElementById(idz).value) {
document.formvalidator.handleResponse(false, el);
flag = flag + 1;
}
}
}
}
}
else {
var valid = document.formvalidator.isValid(f);
}
if(flag == 0 || valid == true){
f.check.value='<?php echo JUtility::getToken(); ?>';//send token
}
else {
alert('<?php echo JText::_('JBJOBS_FIEDS_HIGHLIGHTED_RED_COMPULSORY'); ?>');
return false;
}
return true;
}
External js file:
var JFormValidator = new Class(
{
initialize : function() {
this.handlers = Object();
this.custom = Object();
this.setHandler("username", function(b) {
regex = new RegExp("[<|>|\"|'|%|;|(|)|&]", "i");
return !regex.test(b)
});
this.setHandler("password", function(b) {
regex = /^\S[\S ]{2,98}\S$/;
return regex.test(b)
});
this.setHandler('passverify',
function (value) {
return ($('password').value == value);
}
); // added March 2011
this.setHandler("numeric", function(b) {
regex = /^(\d|-)?(\d|,)*\.?\d*$/;
return regex.test(b)
});
this
.setHandler(
"email",
function(b) {
regex = /^[a-zA-Z0-9._-]+(\+[a-zA-Z0-9._-]+)*#([a-zA-Z0-9.-]+\.)+[a-zA-Z0-9.-]{2,4}$/;
return regex.test(b)
});
var a = $$("form.form-validate");
a.each(function(b) {
this.attachToForm(b)
}, this)
},
setHandler : function(b, c, a) {
a = (a == "") ? true : a;
this.handlers[b] = {
enabled : a,
exec : c
}
},
attachToForm : function(a) {
a.getElements("input,textarea,select")
.each(
function(b) {
if (($(b).get("tag") == "input" || $(b)
.get("tag") == "button")
&& $(b).get("type") == "submit") {
if (b.hasClass("validate")) {
b.onclick = function() {
return document.formvalidator
.isValid(this.form)
}
}
} else {
b.addEvent("blur", function() {
return document.formvalidator
.validate(this)
})
}
})
},
validate : function(c) {
c = $(c);
if (c.get("disabled")) {
this.handleResponse(true, c);
return true
}
if (c.hasClass("required")) {
if (c.get("tag") == "fieldset"
&& (c.hasClass("radio") || c.hasClass("checkboxes"))) {
for ( var a = 0;; a++) {
if (document.id(c.get("id") + a)) {
if (document.id(c.get("id") + a).checked) {
break
}
} else {
this.handleResponse(false, c);
return false
}
}
} else {
if (!(c.get("value"))) {
this.handleResponse(false, c);
return false
}
}
}
var b = (c.className && c.className
.search(/validate-([a-zA-Z0-9\_\-]+)/) != -1) ? c.className
.match(/validate-([a-zA-Z0-9\_\-]+)/)[1]
: "";
if (b == "") {
this.handleResponse(true, c);
return true
}
if ((b) && (b != "none") && (this.handlers[b])
&& c.get("value")) {
if (this.handlers[b].exec(c.get("value")) != true) {
this.handleResponse(false, c);
return false
}
}
this.handleResponse(true, c);
return true
},
isValid : function(c) {
var b = true;
var d = c.getElements("fieldset").concat($A(c.elements));
for ( var a = 0; a < d.length; a++) {
if (this.validate(d[a]) == false) {
b = false
}
}
new Hash(this.custom).each(function(e) {
if (e.exec() != true) {
b = false
}
});
return b
},
handleResponse : function(b, a) {
if (!(a.labelref)) {
var c = $$("label");
c.each(function(d) {
if (d.get("for") == a.get("id")) {
a.labelref = d
}
})
}
if (b == false) {
a.addClass("invalid");
a.set("aria-invalid", "true");
if (a.labelref) {
document.id(a.labelref).addClass("invalid");
document.id(a.labelref).set("aria-invalid", "true");
}
} else {
a.removeClass("invalid");
a.set("aria-invalid", "false");
if (a.labelref) {
document.id(a.labelref).removeClass("invalid");
document.id(a.labelref).set("aria-invalid", "false");
}
}
}
});
document.formvalidator = null;
window.addEvent("domready", function() {
document.formvalidator = new JFormValidator()
});
Where would I edit the code as some of you have answered below?
with jquery js library, scroll to element (id selector or class)
<p class="error">There was a problem with this element.</p>
This gets passed to the ScrollTo plugin in the following way.
$.scrollTo($('p.error:1'));
see source
Using jQuery's .each, loop over the fields. On every iteration the item that is being invesitigated will be under the this variable.
Therefore, this.id gives the id of the element you're looking for. Store these to collect all the incorrect fields, then highlight them or print their names in a message.
Keep in mind, this is the basic idea, I cannot give an actual answer until you show the code that handles the form.
Kind regards,
D.
You can have your isValid routine return the error message instead of returning a boolean.
In isValid, you can build up the error message to include the field names with errors.
Instead of checking "valid == true", you will check "errorMessage.length == 0".
If you want to focus on an error field (you can only focus on one), then do that in the isValid routine as well.
function isValid(f) {
var errorMessage = "";
var errorFields = "";
var isFocused = false;
...
if (field has an error) {
errorFields += " " + field.name;
if (!isFocused) {
field.focus();
isFocused = true;
}
}
...
if (errorFields.length > 0) {
errorMessage = "Errors in fields: " + errorFields;
}
return (errorMessage);
}
then, in your calling routine:
var errorMessage = isValid(f);
if (flag == 0 || errorMessage.length == 0) {
f.check.value='<?php echo JUtility::getToken(); ?>';//send token
}
else {
alert(errorMessage);
return false;
}
return true;