Can anyone help me understand why my recursive string reversal function is returning undefined?
const reverse = (str) => {
const looper = (str, index) => {
if (index < 0) {
return '';
}
return str[index] + looper(str, index - 1);
};
return looper(str, str.length - 1); // Added 'return' statement here
};
console.log(reverse('Hello World!'));Make sure to include a return statement in your main function
const reverseString = function(str) {
const recursiveReverse = function(str, index) {
if(index < 0) {
return '';
}
return str[index] + recursiveReverse(str, index - 1);
};
return recursiveReverse(str, str.length - 1);
};
console.log(reverseString('Lorem Ipsum!'));Here is an alternative method using destructuring
const reversedString = ([firstChar,...remainingChars]) =>
firstChar === undefined
? ''
: reversedString(remainingChars) + firstChar
console.log (reversedString('hello world'))
// 'dlrow olleh'
console.log (reversedString(''))
// ''Now let's optimize it with a tail call
const reversedString = ([firstChar,...remainingChars], callback = char => char) =>
firstChar === undefined
? callback('')
: reversedString(remainingChars, nextChar =>
callback(nextChar + firstChar))
console.log(reversedString('hello world'))
// 'dlrow olleh'
console.log(reversedString(''))
// ''Next, we'll attempt the same without using destructuring
const reversedString = characters =>
characters.length === 0
? ''
: reversedString(characters.slice(1)) + characters.slice(0, 1)
console.log(reversedString('hello world'))
// 'dlrow olleh'
console.log(reversedString(''))
// ''Let's try implementing it with a tail call as well
const reversedString = (characters, callback = char => char) =>
characters.length === 0
? callback('')
: reversedString(characters.slice(1), nextChar =>
callback(nextChar + characters.slice(0,1)))
console.log(reversedString('hello world'))
// 'dlrow olleh'
console.log(reversedString(''))
// ''Some may prefer to use .substr instead of .slice and .concat instead of + – the choice is yours
const reversedString = (characters, callback = char => char) =>
characters.length === 0
? callback('')
: reversedString(characters.substr(1), nextChar =>
callback(nextChar.concat(characters.substr(0,1))))
console.log(reversedString('hello world'))
// 'dlrow olleh'
console.log(reversedString(''))
// ''I encountered an issue while compiling my project: PS C:\Users\hasna\Downloads\A La Marocaine git - Copie\ALaMarocaineFinal\frontend\src\app> ng serve Compiling @angular/forms : es2015 as esm2015 An unhandled exc ...
Is there any benefit to using hasOwnProperty in a loop when an object will always have properties? Take this scenario: const fruits = { banana: 15, kiwi: 10, pineapple: 6, } for (let key in fruits) { if (fruits.hasOwnProperty(key)) { ...
I am facing an issue with the response.redirect command in my webmethod call. Here is a snippet of my code: HTML: <a onclick="proximaAula()">Next Lesson -></a> JS: function proximaAula() { var tipo = getParameterByName('t' ...
Within my AngularJS app, I've come across the following code: example.html <div> <p>{{name}}</p> </div> <div> <button ng-click="someFunction()"></button> </div> exa ...
Currently, I am in the process of developing a travel website using Ruby on Rails 4 which heavily relies on Javascript (or Coffeescript) for functionalities such as Google Maps and other APIs. The workflow involves making an initial call to the server, con ...
Recently diving into the world of react/nodejs/express/javascript, I encountered an interesting challenge: My goal is to retrieve a number, increment it by 1, use this new number (newFreshId) to create a new javascript object, and finally add this event t ...
My task involves creating dynamic fields with labels based on user input. To clarify: I prompt the user to select a date range, and I want to generate label and input field for each date within that range. To achieve this, I implemented an AJAX function ...
Having trouble modifying the CSS of a class in my HTML file. I've been struggling with this for quite some time and can't figure out what I'm doing wrong. (I've already attempted multiple versions, but nothing seems to work) Here' ...
I am having an issue retrieving the value of a radio button that is generated using jQuery. I suspect there may be some problems with event handling. Below is my code: HTML <div id="divOption1"></div> The jQuery script to generate t ...
Wondering how to pass data from the parent component (Home route) to the child component (playlist route) using props? Encountering a "TypeError: Cannot read property 'length' of undefined" error in the child component? These two components are c ...
Greetings everyone, Lately, I've been on the lookout for a straightforward JavaScript class framework that focuses solely on basic inheritance. After some research, I stumbled upon John Resig's sample framework shared on his blog, and it seems t ...
Let's discuss a scenario where I have to decide whether to display a block based on a certain condition. Here is an example array structure: const data = [ { name: "item1" , values : [0,0,0,0,0]}, { name: "item2" , values : [0,0,0,0,0]}, { nam ...
For the past two days, I've been attempting to set up apollo on an Angular application. Unfortunately, I keep encountering the following error: The package <a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="ea8b9a85868685c78b8 ...
Currently, I am utilizing the Open Weather Map's free API which allows me to make 1000 API calls per day through their One Call API. However, there is no built-in feature for tracking these calls in the Open Weather Map platform. To address this issue ...
I have successfully implemented a calendar feature with a "More" button on each day to display additional events if there are more than three. However, I am facing an issue where clicking the button triggers the dropdown for all days instead of just the se ...
I created an input field with a hover effect that reveals an edit button upon mouseover. After clicking the button, I disabled the hover event using jQuery. However, I am unable to re-enable this hover event by clicking the same button. Here is the code s ...
Seeking a way to navigate between PHP and JavaScript worlds with confidence. There's a collection of PHP functions stored neatly in custom_functions.php waiting to be called from JavaScript. As I delve into the realm of JavaScript and jQuery, my fam ...
When an error occurs in the catch block, Axios does not return errors in JSON format. Sign-up Page const handleSignup = async () => { try { setIsLoading(true) const res = await axios({ url: 'http://10.0.2.2:8080/signup&ap ...
Transitioning from PHP & Java/Android development to web app development can feel overwhelming, especially with the abundance of Javascript Frameworks available. Check out this comparison of popular JavaScript frameworks View a list of the top JavaSc ...
When working with AngularJS and a select options collection, I encountered an issue. Everything worked fine when I manually added option tags in the HTML, but it didn't work when trying to add items from Angular. This is my code: <div ng-controll ...