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CounterWarm Up Question
Build a simple counter that increments whenever a button is clickedStackFree
Implement a stack data structure containing the common stack methodsType UtilitiesFree
Implement utilities to determine primitive variable types in JavaScriptInsertion SortFree
Implement a function that performs an insertion sortBinary SearchFree
Implement a function that performs binary search on an array of numbersDebounceFree
Implement a function to limit how many times a function can be executed by delaying the execution of the function until after a specified time after its last execution attemptHeap SortFree
Implement a function that performs a heap sortQueueFree
Implement a queue data structure containing the common queue methodsTabsFree
Build a tabs component that displays a list of tab elements and one associated panel of content at a timeFlattenFree
Implement a function that recursively flattens an array into a single level deepMerge SortFree
Implement a function that performs a recursive merge sortPromise.allFree
Implement the Promise.all() function that resolves to an array of results if all the input elements are resolved or rejects otherwiseQuick SortFree
Implement a function that performs a recursive quick sortTodo ListFree
Build a Todo list that lets users add new tasks and delete existing tasksTopological SortFree
Implement a function that performs a topological sortTraffic LightFree
Build a traffic light where the lights switch from green to yellow to red after predetermined intervals and loop indefinitelyDeep CloneFree
Implement a function that performs a deep copy of a valueDigital ClockFree
Build a 7-segment digital clock that shows the current timeJob BoardFree
Build a job board that displays the latest job postings from Hacker NewsClampPremium
Implement a function to clamp a number within the inclusive lower and upper boundsArray.prototype.squarePremium
Implement a custom Array.prototype.square() method that squares the values in an arrayChunkPremium
Implement a function that creates an array of elements split into smaller groups of a specified sizeCompactPremium
Implement a function that creates an array with all falsey values removedDifferencePremium
Implement a function that finds the difference in values between arraysDrop Right WhilePremium
Implement a function that excludes elements from the end of an array until the predicate returns falseDrop WhilePremium
Implement a function that excludes elements from the beginning of an array until the predicate returns falseFillPremium
Implement a function that fills an array with values within specified indicesFind IndexPremium
Implement a function that returns the index of the first element in the array that satisfies the provided testing functionFind Last IndexPremium
Implement a function that returns the index of the last element in the array that satisfies the provided testing functionGetPremium
Implement a function to safely access deeply-nested properties in JavaScript objectsIn RangePremium
Implement a function to check if a number falls between two numbersOncePremium
Implement a function that accepts a callback and restricts its invocation to at most onceSelection SortPremium
Implement a function that performs a selection sortUnique ArrayPremium
Implement a function to remove all duplicate values from an arrayAccordionPremium
Build an accordion component that a displays a list of vertically stacked sections with each containing a title and content snippetArray.prototype.filterPremium
Implement the Array.prototype.filter() methodArray.prototype.mapPremium
Implement the Array.prototype.map() methodArray.prototype.reducePremium
Implement the Array.prototype.reduce() methodFlight BookerPremium
Build a component that books a flight for specified datesFunction.prototype.bindPremium
Implement the Function.prototype.bind() function that creates a new function with the `this` keyword set to a provided valueGenerate TablePremium
Generate a table of numbers given the rows and columnsjQuery.cssPremium
Implement a jQuery-like function that sets the style of a DOM elementProgress BarPremium
Build a progress bar component that shows the percentage completion of an operationProgress BarsPremium
Build a list of progress bars that fill up gradually when they are added to the pagePromise.racePremium
Implement the Promise.race() function that resolves or rejects when any of the input elements are resolved or rejectedSumPremium
Implement a function that sums numbers by accepting a number and allows for repeated calling with more numbers until it is not called with any numberTemperature ConverterPremium
Build a temperature converter widget that converts temperature values between Celsius and FahrenheitCurryPremium
Implement a function that transforms a function that takes multiple arguments into a function that can be repeatedly called with only one argument at a timeIs EmptyPremium
Implement a function to check if a value is an empty object, collection, map, or setLimitPremium
Implement a function that accepts a callback and restricts its invocation to at most N timesThrottlePremium
Implement a function to control the execution of a function by limiting how many times it can execute over timeAccordion IIPremium
Build an accessible accordion component that has the right ARIA roles, states, and propertiesAccordion IIIPremium
Build a fully accessible accordion component that has keyboard support according to ARIA specificationsAnalog ClockPremium
Build an analog clock where the hands update and move like a real clockCamel Case KeysPremium
Implement a function to convert all the keys in an object to camel caseClassnamesPremium
Implement a function that conditionally joins CSS class names togetherCurry IIPremium
Implement a function that transforms a function that takes multiple arguments into a function that can be repeatedly called with any number of argumentsDebounce IIPremium
Implement a debounce function that comes with a cancel method to cancel delayed invocations and a flush method to immediately invoke themEvent EmitterPremium
Implement a class that can subscribe to and emit events that trigger attached callback functionsEvent Emitter IIPremium
Implement a class that can subscribe to and emit events that trigger attached callback functions. Subscription objects are returned and can unsubscribe itselfgetElementsByTagNamePremium
Implement a function to get all DOM elements that match a tagGrid LightsPremium
Build a grid of lights where the lights deactivate in the reverse order they were activatedHTML SerializerPremium
Implement a function to serialize an object into a HTML string with indentationIdentical DOM TreesPremium
Implement a function to determine if two DOM trees are the samejQuery Class ManipulationPremium
Implement a set of jQuery-like functions that manipulates classes on a DOM elementLike ButtonPremium
Build a Like button that changes appearance based on the statesList FormatPremium
Implement a function that formats a list of items into a single readable stringProgress Bars IIPremium
Build a list of progress bars that fill up gradually in sequence, one at a timePromise.allSettledPremium
Implement the Promise.allSettled() function that resolves to an array of outcomes when all the input elements are either resolved or rejectedPromise.anyPremium
Implement the Promise.any() function that resolves when any of the input elements are resolvedSquash ObjectPremium
Implement a function that returns a new object after squashing the input object into a single level of depthStar RatingPremium
Build a star rating component that shows a row of star icons for users to select the number of filled stars corresponding to the ratingTabs IIPremium
Build a semi-accessible tabs component that has the right ARIA roles, states, and propertiesTabs IIIPremium
Build a fully accessible tabs component that has keyboard support according to ARIA specificationsText SearchPremium
Implement a function to highlight text if a searched term appears within itDeep EqualPremium
Implement a function that determines if two values are equalgetElementsByClassNamePremium
Implement a function to get all DOM elements that contain the specified classesProgress Bars IIIPremium
Build a list of progress bars that fill up gradually concurrently, up to a limit of 3Text Search IIPremium
Implement a function to highlight text if searched terms appear within itTic-tac-toePremium
Build a tic-tac-toe game that is playable by two playersSignup FormPremium
Build a signup form that does validation on user details and submits to a back end APIStopwatchPremium
Build a stopwatch widget that can measure how much time has passedTransfer ListPremium
Build a component that allows transferring of items between two listsUndoable CounterPremium
Build a counter with a history of the values and ability to undo/redo actionswhack-a-molePremium
Build a popular arcade game where players attempt to hit moles as they pop up from holes in a boardMemory GamePremium
Build a memory game where the player needs to match pairs of cardsCurry IIIPremium
Implement a function which transforms a function which takes variadic arguments into a function that can be repeatedly called with any number of argumentsProgress Bars IVPremium
Build a list of progress bars that fill up gradually concurrently, up to a limit of 3 and allows for pausing and resumingData SelectionPremium
Implement a function to filter rows of data matching a specified requirementTable of ContentsPremium
Implement a function to construct a table of contents from a HTML documentDeep Clone IIPremium
Implement a function that performs a deep copy of a value, but also handles circular referencesTic-tac-toe IIPremium
Build an N x N tic-tac-toe game that requires M consecutive marks to winTransfer List IIPremium
Build a component that allows transferring of items between two lists, bulk selection/unselection of items, and adding of new itemsJSON.stringifyPremium
Implement a function that converts a JavaScript value into a JSON stringWordlePremium
Build Wordle, the word-guessing game that took the world by storm