My Codewars Solutions

The validBraces function checks if a string of braces (), [], and {} is valid by using a stack. It ensures every opening brace has a corresponding closing brace in the correct order, returning true if valid and false if not.

This JavaScript code demonstrates how to use the forEach method to iterate over an array of numbers. In the first snippet, it simply doubles each number and logs the result to the console. The second snippet enhances the functionality by not only doubling each number but also logging the element's index and the entire array during each iteration.

This JavaScript code takes an array of numbers, changes the sign of each element (negatives become positives and positives become negatives), and then sorts the resu lting array in ascending order. The final sorted array is logged to the console.

This code counts the occurrences of each letter in an array using an object. It iterates through the array with forEach, updating the count for each letter and logs the result.

This code snippet defines a function that counts how many times a specified value appears within an array of numbers. Given an array of scores, it demonstrates how to find the frequency of occurrences of the number 100 in that array using the reduce method. The result is then printed to the console.

This code snippet demonstrates how to check the primitive data types in JavaScript using the typeof operator. It shows that numerical values (like 2.5) are of type number, strings (like "one two three") are classified as string, and boolean values (such as false) are identified as boolean.

This section introduces objects in JavaScript as associative arrays, where properties are accessed by unique keys instead of numerical indexes. The provided example defines an object, sampleObject, with several properties and demonstrates updating and accessing these properties, highlighting the flexibility and structure of JavaScript objects.

This section describes methods as functions that serve as properties of JavaScript objects, defining their behavior. An example of a point object with properties x and y, along with methods to move the point, demonstrates how methods can change an object's state. The this keyword indicates the object's context within the methods, highlighting the relationship between methods and object properties.

This code snippet demonstrates how to delete the work property from the email object within a contact object. After the deletion, it logs the result of accessing work (which outputs undefined) and verifies that the private email property still exists and outputs its value, "victoireushindi371@gmail.com.

This code shows how to update a property in a JavaScript object. It highlights the error that occurs when trying to access a property with a space in its name using incorrect syntax.

This code snippet demonstrates how to loop through specific properties of a JavaScript object (contact) by dynamically constructing the property names ("email_1" and "email_2") within a for loop and logging their values to the console.

The getClothing function provides clothing recommendations based on the isCold boolean input, returning "Grab a jacket!" for cold weather and "It’s a shorts kind of day." for warm weather. It utilizes block-scoping with let for the messages.

This code creates a contact object and checks if the notes property is undefined. If it is, it sets notes to "something really important" and logs this value.

This JavaScript code calculates and logs the area of a circle with a radius of 5 using the formula Area = π×r×r. The calculation is performed when the webpage finishes loading. The area is logged as 78.55 in the console.

This JavaScript code calculates the area of a circle using local and global variables. On page load, it logs the global pi (3.142) and calculates the area using a local pi (10). The area of the circle with radius 5 is logged as 250.

This JavaScript code waits for the window to load, then defines an array of meat types. After the window loads, it logs each meat type to the console, separated by spaces, using the spread operator for easy visibility in debugging or informational contexts.

This code merges an array of numbers (1-5) with additional numbers (6-10) using the spread operator and logs the result to the console.

This code defines an array with three numbers (3, 5, 7) and a function that adds its three arguments. It uses the spread operator to pass the array elements as individual arguments to the function and logs the sum (15) to the console.

This example demonstrates how to use template strings for simple variable interpolation. The value of the name variable is inserted into the greeting string, resulting in "Hello, Victoire!

 This example shows how template strings can create multi-line strings without the need for concatenation or escape characters. The output maintains the line breaks as shown in the code.

Here, template strings can embed expressions directly within the string. The values of a and b, as well as their sum, are calculated and included seamlessly in the output: "The sum of 5 and 10 is 15."

In this example, a method within an object uses a template string to create a greeting. The properties name and age are interpolated, producing "My name is Bob and I am 30 years old."

This code snippet runs when the window loads, creating a multi-line string using template literals. The string greets and introduces "Victor," maintaining the format with line breaks. Inspect the page to check the output in tthe console

 In this example, includes() is used to check if the substring "fox" exists within the sentence. It returns true, indicating that the substring is present.

This example demonstrates startsWith(), which checks if the string greeting starts with "Hello". The method returns true, confirming the string begins with the specified value.

Here, endsWith() is used to verify if the filename ends with ".pdf". The method returns true, indicating that the string concludes with the specified suffix.

In this example, repeat() is employed to create a string by repeating "ha" three times, resulting in "hahahaha!!!". This method is useful for generating repeated patterns efficiently.

This code replaces "World" with "Codewars" in the string "Hello World!!" and logs "Hello Codewars!!" to the console upon window load. It illustrates the use of the replace() method in JavaScript.

This code checks if "goodbye" starts with "by" from the 4th index, returning true. The result is logged to the console upon window load.

 This code checks if "goodbye" ends with "good" when assessing up to the 3rd last character, returning true. The result is logged to the console on window load.

This code defines a ninja object with a method called chop, which simulates a chopping action by logging a message to the console every second. The method takes a parameter x, which represents the number of times the ninja will "chop" before stopping. The window.onload function ensures that the simulation starts once the webpage has fully loaded.

This code defines an arrow function add that takes two parameters, a and b, and returns their sum. When called with arguments 2 and 3, it logs 5 to the console.

This code defines an arrow function greet that takes no parameters and returns the string "Hello, World!". It logs the greeting to the console when called.

This code illustrates an arrow function square that takes a single parameter x and returns its square. When called with 4, it logs 16 to the console.

Here, the arrow function multiplyAndLog accepts two parameters, multiplies them, logs the result, and returns it. When called with 3 and 5, it logs 15 to the console.

This code defines a ninja object with a method called chop, which simulates a chopping action by logging a message to the console every second. The method takes a parameter x, which represents the number of times the ninja will "chop" before stopping. The window.onload function ensures that the simulation starts once the webpage has fully loaded.

This code creates a new Set called mySet initialized with the numbers 1 to 5. It logs the Set, which contains these unique values.

In this example, a new Set is created, and the values 1 and 2 are added. Adding 1 again (a duplicate) has no effect. The logged Set contains only the unique values 1 and 2.

This code creates a Set with the letters 'a', 'b', and 'c'. The has method checks for the presence of 'b' (returns true) and 'd' (returns false), which are logged to the console.

This code initializes a Set with the values 1, 2, and 3. The delete method removes the value 2, and the logged Set now contains only 1 and 3.

This example demonstrates the use of the forEach method to iterate over a Set. Each value in the Set (1, 2, 3) is logged to the console in turn.

This code snippet illustrates the use of a JavaScript Set to manage a collection of unique names. It initializes a Set, adds several names (including a duplicate), and removes one name. The code checks for the presence of a specific name (Victoire), attempts to delete a name that has already been removed, and logs the size of the Set along with its current contents. The Set ensures that only unique names are stored, demonstrating its capabilities in handling duplicates and membership checks.

This code snippet demonstrates how to remove duplicate names from an array of family members using a JavaScript Set. It starts with an array that contains several names, including duplicates. By creating a Set from the array, it automatically filters out the duplicates. The code then converts the Set back into an array and logs both the unique Set and the refined array of family members to the console. This showcases the effectiveness of Set in managing unique values in JavaScript.

This is the correct way to use let. Use let to declare variables when you plan on changing the value of a variable later in your code.

This code refactor demonstrates the conversion of variable declarations from var to let and const in a JavaScript program. By using const for unchanging constants and arrays, and let for block-scoped variables such as loop indices, the code enhances readability, maintains better scoping practices, and prevents potential issues related to variable hoisting and reassignment.

This code defines objects for a student and a teacher, constructs a message instructing the student to meet the teacher in a specified room to pick up their report card. Prior to ES6, the old way to concatenate strings together was by using the string concatenation operator ( + ).

This code constructs a multi-line note to the teacher, excusing the student for being ill. It demonstrates the use of string concatenation with the newline character (\n) to format the note across multiple lines, which can become complex compared to single-line strings.

This code defines an object for a cheetah and a function that generates an HTML trading card for the animal using template literals, allowing for cleaner and more readable multi-line strings. It replaces the concatenation with ${} syntax to interpolate the object properties directly into the HTML structure.

Create reusable functions to encapsulate logic.

Learn to handle events in the DOM using JavaScript.

This code creates a Promise that resolves if a simple condition (1 + 1 equals 2) is met, otherwise it rejects. A promise that resolves with the string 'success' or rejects with the string 'failed'.

his code creates a promise that simulates an asynchronous operation with a delay of 1 second. The promise resolves with "OK" if the operation is successful, otherwise it rejects with "Error".

This code defines a function to display messages in the console. It calls this function with "Hello" and "Goodbye" to demonstrate simple function usage.

JavaScript functions are executed in the sequence they are called. Goodbye

JavaScript functions are executed in the sequence they are called. The result of the calculation is: 15

This code provides a greet function that uses parameter checks to set default values for name and greeting. If no arguments are passed, it defaults to greeting "Student" with "Welcome".

Just like array destructuring with array defaults, a function can have an object be a default parameter and use object destructuring:

You can combine default function parameters with destructuring(opens i n a new tab) to create some pretty powerful functions!

This JavaScript code demonstrates class inheritance with a base Animal class and derived classes (Rabbit, Fish, Hawk) that share common properties and behaviors, utilizing the super keyword to access parent class methods and properties.

This code defines a Tree class and a Maple subclass that manage tree attributes and seasonal changes. The Tree class initializes properties like size and leaf colors based on seasons, while the Maple class adds functionality to manage sap quantity and gather syrup, as well as overrides methods to adjust syrup during seasonal changes.

This code snipped is all about JavaScript Function and Callback Function

Create a Bicycle subclass that extends the Vehicle class. The Bicycle subclass should override Vehicle's constructor function by changing the default values for wheels from 4 to 2 and horn from 'beep beep' to 'honk honk'.

A symbol is a unique and immutable data type that is often used to identify object properties. To create a symbol, you write Symbol() with an optional string as its description. const sym1 = Symbol('apple'); console.log(sym1); Symbol(apple)

The iterable protocol is used for defining and customizing the iteration behavior of objects.

The iterator protocol is used to define a standard way that an object produces a sequence of values. What that really means is you now have a process for defining how an object will iterate. This is done through implementing the .next() method.

This code snippet demonstrates how to check the length of a Set in JavaScript. It creates a Set with # unique values and logs the size of the Set to the console. The output shows that the Set contains # elements.

Because the .values() method returns a new iterator object (called SetIterator), you can store that iterator object in a variable and loop through each item in the Set using .next().

An easier method to loop through the items in a Set is the for...of loop.

This code creates a Set to store unique ice cream flavors, adds four flavors, removes "strawberry," and logs the remaining flavors.

A WeakSet is just like a normal Set with a few key differences:

1. a WeakSet can only contain objects
2. a WeakSet is not iterable which means it can’t be looped over
3. a WeakSet does not have a .clear() method

This snippet shows how to create a WeakSet in JavaScript to store unique flavor objects. It defines two flavor objects and adds them to the WeakSet, ensuring only unique references are kept.

This function converts an object into an array, sorts it by values from highest to lowest, and then maps it back to strings formatted as "key: value".

The purpose of Math.random() is to generate a random decimal number between 0 (inclusive) and 1 (exclusive). It's useful in situations where you need unpredictability, like: Creating random game elements (e.g., random positions, dice rolls) Randomizing choices or options Simulating chance or probability events Generating random values for experiments or simulations In short, it helps introduce randomness into your programs!

Generate a random number and display it in the console.

Generate five random numbers and store them in an array.

Create a function that returns a random number between 0 and 1 when called.

Generate a random number and check if it’s greater than 0.5. Log "High" if yes, otherwise "Low".

Generate a random number, multiply it by 10, and round it to the nearest whole number.

Math.floor() is a JavaScript method that rounds a decimal down to the nearest whole number (integer).

The code calculates and prints the number of full weeks and remaining days in a year (assuming 365 days).

This code uses a switch statement to check the value of the food variable (which is set to 'salad'). Since 'salad' doesn't match the case values 'oyster' or 'pizza', the default case is executed, printing "Enjoy your meal" to the console

The code demonstrates how to delete a property from a nested object in JavaScript. It initializes a contact object with email addresses, then uses the delete operator to remove the work email property. Consequently, accessing the deleted property returns undefined, while accessing other existing properties returns their values.

The code initializes a contact with known email addresses, adds a new "other" email address, and then logs all existing email addresses to verify the additions.

This JavaScript code snippet demonstrates the correct way to access and modify properties within an object. The code shows that while you can use bracket notation (e.g., contact["first name"]) to access properties, especially those with spaces in their names, attempting to use dot notation (e.g., contact.first name) with a space or string directly causes a syntax error. This highlights the importance of using bracket notation when property names contain spaces or are dynamically determined.

This code initializes a contact object with a name and email. It then checks if the notes property exists. If notes is falsy (e.g., undefined), it sets contact.notes to "something really important". Finally, it prints the updated contact object to the console.

This code snippet demonstrates how to access a property ('notes') of an object ('contact') and print its value to the console after first verifying that the property exists within the object using the in operator. This prevents errors that might occur if the property was undefined.

This code snippet defines a contact object with telephone and email properties. It then uses a for...in loop to iterate through the object's properties, printing each property name to the console.

Write a function which calculates the average of the numbers in a given array.

You're writing code to control your town's traffic lights. You need a function to handle each change from green, to yellow, to red, and then to green again. Complete the function that takes a string as an argument representing the current state of the light and returns a string representing the state the light should change to. For example, when the input is green, output should be yellow.

Adds all numbers in an array, resulting in 15.

Create a method that takes as input a name, city, and state to welcome a person. Note that name will be an array consisting of one or more values that should be joined together with one space between each, and the length of the name array in test cases will vary.

Given an array of integers. Return an array, where the first element is the count of positives numbers and the second element is sum of negative numbers. 0 is neither positive nor negative. If the input is an empty array or is null, return an empty array.

You will be given a list of strings. You must sort it alphabetically (case-sensitive, and based on the ASCII values of the chars) and then return the first value. The returned value must be a string, and have "***" between each of its letters.

This code demonstrates how Object.assign() copies properties from one object to another, creating a new object with the same property values but different references. It highlights that while objects may have identical content, they are considered different in memory unless they share the same reference.

This snippet shows how Object.assign() updates an existing object by adding new properties and overwriting existing ones. Here, it adds age and updates country in the me object, resulting in a combined object with the latest property values.

The map() method creates a new array populated with the results of calling a provided function on every element in the calling array. It does not execute the function for empty elements. In this example, it is used to create a new array of squares from an existing array of numbers.

Demonstrates the use of a regular expression in JavaScript to test whether the string "hello" appears at the beginning of a given input string. The code logs the result of testing two different strings against the pattern.

This regular expression pattern matches any single digit character (0-9). Useful for validating or extracting numeric digits from strings.

This regular expression pattern matches only the exact string "cat". It does not match substrings or variations; the input must be exactly "cat".

This pattern uses the word boundary anchor (`\b`) to ensure that the match occurs at the start of a word, followed by the letter 'b' and then zero or more word characters (`\w*`). The global flag (`g`) allows matching all occurrences in a string.

This function logs "Hello!" to the console and then invokes the provided callback function.

This code defines a sum function that adds two numbers and passes the result to a callback function. It demonstrates using callbacks by printing the sum to the console with a separate displayConsole function.

@param {number[]} a - An array of numbers representing character codes. @returns {(number|string)[]} A new array where numbers corresponding to vowels are replaced by their character, others remain unchanged.

This code converts an array of character codes to their corresponding letters using `String.fromCharCode` and logs each letter to the console.

This code uses a regular expression (/[aeiou]/) with the .test() method to check if a string contains at least one lowercase vowel (a, e, i, o, or u). It logs true if a vowel is found and false otherwise.

This code demonstrates how Array.from() can convert a string into an array of characters and how it can transform each element of an array using a mapping function. The first line outputs an array of characters from the string "food", while the second line outputs a new array where each number from [1,2,3] is doubled.

This function iterates through each character of a given string, checks if it is a vowel (a, e, i, o, u), and returns the total number of vowels found.

This code retrieves the character and its Unicode code point from a specific index in a string, then logs both values to the console.

This code defines a function that takes a string and returns an array containing the Unicode character codes for each character in the string. It demonstrates the conversion using the example name "Victoire".

This code defines a function extractVowels that takes a string and returns a new string containing only the vowels from the original input, preserving their order and case.

This code defines a function repeatString(n, s) that returns a string s repeated n times. If n is not a positive integer, it returns an error message. The function uses a for loop to concatenate the string s n times.