Enjoy 20% off all plans by following us on social media. Check out other promotions!

JavaScript Polyfills

Gain proficiency in front end fundamentals by implementing JavaScript and DOM APIs from scratch.

所有练习题目

编码形式

题目列表

  • Type UtilitiesImplement utilities to determine primitive variable types in JavaScript
    语言
    JSTS
  • Type Utilities IIImplement utilities to determine non-primitive variable types in JavaScript
    语言
    JSTS
  • Event EmitterImplement a class that can subscribe to and emit events that trigger attached callback functions
    语言
    JSTS
  • FlattenImplement a function that recursively flattens an array into a single level deep
    语言
    JSTS
  • Promise.allImplement the Promise.all() function that resolves to an array of results if all the input elements are resolved or rejects otherwise
    语言
    JSTS
  • Find IndexImplement a function that returns the index of the first element in the array that satisfies the provided testing function
    语言
    JSTS
  • Find Last IndexImplement a function that returns the index of the last element in the array that satisfies the provided testing function
    语言
    JSTS
  • Function.prototype.applyImplement the Function.prototype.apply() function that calls the function with a given `this` value and arguments as an array
    语言
    JSTS
  • Function.prototype.callImplement the Function.prototype.call() function that calls the function with a given `this` value and provided arguments
    语言
    JSTS
  • Promise.rejectImplement a function to return a Promise object rejected with a reason
    语言
    JSTS
  • Array.prototype.atImplement the Array.prototype.at() method
    语言
    JSTS
  • Array.prototype.filterImplement the Array.prototype.filter() method
    语言
    JSTS
  • Array.prototype.mapImplement the Array.prototype.map() method
    语言
    JSTS
  • Array.prototype.reduceImplement the Array.prototype.reduce() method
    语言
    JSTS
  • Function.prototype.bindImplement the Function.prototype.bind() function that creates a new function with the `this` keyword set to a provided value
    语言
    JSTS
  • Promise.raceImplement the Promise.race() function that resolves or rejects when any of the input elements are resolved or rejected
    语言
    JSTS
  • Array.prototype.concatImplement the Array.prototype.concat() method
    语言
    JSTS
  • Promise.resolveImplement a function to resolve a given value to a Promise
    语言
    JSTS
  • Promise.withResolversImplement a function that returns an object containing a new `Promise` object and two functions to resolve or reject it
    语言
    JSTS
  • Event Emitter IIImplement a class that can subscribe to and emit events that trigger attached callback functions. Subscription objects are returned and can unsubscribe itself
    语言
    JSTS
  • getElementsByTagNameImplement a function to get all DOM elements that match a tag
    语言
    HTMLJSTS
  • JSON.stringifyImplement a function that converts a JavaScript value into a JSON string
    语言
    JSTS
  • Promise.allSettledImplement the Promise.allSettled() function that resolves to an array of outcomes when all the input elements are either resolved or rejected
    语言
    JSTS
  • Promise.anyImplement the Promise.any() function that resolves when any of the input elements are resolved
    语言
    JSTS
  • getElementsByClassNameImplement a function to get all DOM elements that contain the specified classes
    语言
    HTMLCSSJSTS
  • getElementsByTagNameHierarchyImplement a function to get all DOM elements that match a tag hierarchy
    语言
    HTMLJSTS