A better way to learn JavaScript - Built-in Objects
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A better way to learn JavaScript - Built-in Objects

Save Yourself From Another 1000 Hours of Trial and Error Experiences!

About the Book

This book is a second in the series of 5 books on JavaScript.

In Book 1 we learned a lot about JavaScript. In Book 2, we "backfill" the wholes in our knowledge by having a detailed, in-depth look at all the built-in objects in JavaScript.

Understanding all the available methods and properties on built-in objects will do wonders for our confidence as JS developers.

Once you read this book, you can rest assured that whatever JS code comes your way, you'll know where it's coming from and how it works.

Books 1 and 2 are a solid foundation for working with some real-life code, with a lot of code snippets, and specific use cases. This is what Book 3 is about.

However, at the end of Book 2, we'll have a large section with all the code snippets extracted from both Books 1 and 2 (currently at about 90 code snippets, but as this book gets updated, by the end it should have at least 300 code snippets).

Both Books 1 and 2 aim to "draw the map of JavaScript", and are indeed a Better Way to Learn JS, because they are like a story about JavaScript that unwinds right before you.

Join me on this journey!

About the Author

Ajdin Imsirovic
Ajdin Imsirovic

Ajdin Imsirovic is a full-stack web developer who has published several courses (way back in 2015) on the subject of web design and web development. 

Before self-publishing books on Leanpub, he authored four books on front-end development for Packt Publishing:

  1. Vue CLI 3 Quick Start Guide (Build and maintain Vue.js applications quickly with the standard CLI), May 2019
  2. Vue.js Quick Start Guide (Learn how to build amazing and complex reactive web applications easily using Vue.js), October 2018
  3. Elm Web Development (An introductory guide to building functional web apps using Elm), March 2018
  4. Bootstrap 4 Cookbook (Over 75 recipes to help you build elegant and responsive web applications with Bootstrap 4), June 2017

Additionally, he's published a number of books on the Leanpub platform, specifically:

  1. A Better Way to Learn JavaScript - The Basics: https://bit.ly/abwtljs1
  2. A Better Way to Learn JavaScript - Built-in Objects: https://bit.ly/abwtljs2
  3. A Better Way to Learn JavaScript - Useful Snippets: https://bit.ly/abwtljs3
  4. A Better Way to Learn JavaScript - Mini Apps: https://bit.ly/abwtljs4
  5. A Better Way to Learn JavaScript - Advanced JavaScript: https://bit.ly/abwtljs5
  6. Angular From Scratch: https://bit.ly/ai-afs
  7. Vue.js From Scratch: https://bit.ly/ai-vfs
  8. React from Scratch: https://leanpub.com/react-from-scratch
  9. Building Amazing Layouts - Learn the Basics of HTML5, CSS3, and Bootstrap 5: https://bit.ly/bldamzlyts1
  10. Building Amazing Layouts - Bootstrap 5 Layouts in Depth: https://bit.ly/bldamzlyts2
Ajdin Imsirovic

Episode 208

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Reader Testimonials

Peter Lin
Peter Lin


Hi Ajdin, I have been really enjoying learning from your 5 books of a-better-way-to-learn-javascript. It is really a better learning experience comparing to my reading of other JavaScript books or video courses. I have been very happy that I found and purchased them at leanpub.com. Excellent!! :)

Table of Contents

  • Introduction
  • Chapter 1: An overview of standard built-in objects
  • Chapter 2: The Object object
    • The Object object
    • The Object object’s methods and properties
    • Static methods on the Object object
    • Object object’s static “create” methods
    • Object object’s static “read” methods
    • Object object’s static “update” methods
    • Object object’s static “freeze” methods
    • Object object’s instance properties and methods
    • Object object’s instance properties
    • Object object’s instance methods
    • Object object’s deprecated instance methods
    • Object object’s “checker” instance methods
    • Object object’s “conversion” instance methods
  • Chapter 3: The Function object
    • The Function object
    • Function.prototype.apply()
    • Whip up “Array.max” method with Function.prototype.apply()
    • Function.prototype.call()
    • Function.prototype.bind()
    • Why bind a function?
    • Use bind() to cement the context of this
    • Use bind() to partially apply a function
    • Use bind() to pass context to setTimeout()
    • Use bind() for invocation shortcuts
    • Function.prototype.toString()
  • Chapter 4: The Boolean object
    • The Boolean object
    • The Boolean constructor and boolean primitives behave differently
    • Don’t convert a non-boolean using the constructor!
    • Built-in Boolean object’s instance methods
  • Chapter 5: The Symbol object
    • The Symbol object
    • There’s no “shorthand syntax” for the symbol primitive
    • Symbol() is a factory function
    • Why is the Symbol() not a true constructor?
    • Using a symbol’s optional description argument
    • How to get a symbol’s description?
    • Why Symbols in ES6?
    • How to add a symbol to an object literal?
    • Getting the value of a symbol key from an object
    • Symbols are excluded from for...in loops
    • Pseudo-hidden properties on objects are made possible by symbols
    • Why symbols in ES6, again?
    • Why symbols are not truly hidden?
    • Symbols are skipped in JSON conversions
    • Symbols can be used to avoid code collisions
    • Symbols can be used to fix ENUM lists
    • Use symbols as metadata storage
    • The global symbol registry
    • The difference between local and global symbols
    • Well-known symbols
    • Conclusion
  • Chapter 6: Built-in collection objects: Array
    • The Array object
    • The Array[@@species] accessor
    • The Array.prototype[@@iterator]() instance method
    • The Array.prototype[@@unscopables] instance property
    • The Array.from() static method
    • The Array.of() static method
    • The Array.prototype.entries() instance method
    • The Array.prototype.keys() instance method
    • The Array.prototype.values() instance method
    • The Array.prototype.findIndex() instance method
    • The Array.prototype.lastIndexOf() instance method
    • The Array.prototype.toLocaleString() instance method
    • The Array.prototype.toString() instance method
    • The Array.prototype.reduceRight() instance method
  • Chapter 7: Built-in collection objects: typed array objects
    • Why typed arrays in JS?
    • The immutability of Blob
    • Extracting Blob slices
  • Chapter 8: Built-in collection objects: maps, sets, weak maps, weak sets, and arguments
    • The Map object
    • The Set object
    • The WeakMap object
    • The WeakSet object
    • The arguments array-like object
  • Chapter 9: Error objects
    • How to throw errors in JS?
    • How to catch errors in JS gracefully?
    • How to customize error messages in JS?
    • What’s a stack trace?
    • Strict mode and errors
    • Browser sniffing and errors
    • Errors and debugging
  • Chapter 10: Async-related and JSON-related objects
    • An overview of built-in async-related objects, their properties, and methods
    • The Promise() constructor and the then() instance method
    • Wrapping methods into promise objects
    • Passing one more promise to the resolveFn
    • The Promise.all(iterable) static method
    • The Promise.allSettled(iterable) static method
    • The Promise.any(iterable) static method
    • The Promise.race(iterable) static method
    • The Promise.reject(reason) static method
    • The Promise.resolve(value) static method
    • The GeneratorFunction() and AsyncFunction()
    • Using Generator.prototype.next()
    • Using Generator.prototype.return()
    • Using Generator.prototype.throw()
    • The JSON object
    • JSON.parse(text[, reviver])
    • JSON.stringify(value[, replacer[, space]])
    • The ArrayBuffer object
    • The SharedArrayBuffer object
    • The Atomics object
    • The DataView object
  • Chapter 11: String, number, date, and internationalization objects
    • String object’s built-in methods and properties
    • “CREATE” string methods
    • “READ location” string methods
    • “READ inclusion” string methods
    • “READ string comparison” string methods
    • “UPDATE join and split” string methods
    • “UPDATE spacing” string methods
    • “UPDATE letter casing” string methods
    • DELETE
    • The String.prototype regex (pattern-matching) methods
    • Number object’s built-in methods and properties
    • Date object’s built-in methods and properties
    • Intl object’s built-in methods and properties
  • Chapter 12: Regular expressions in JavaScript
    • What is a regular expression in JavaScript?
    • Regular expression literal
    • Check if an object is of RegExp type
    • RegExp constructor function
    • RegExp modifiers (aka “pattern flags”)
    • String.prototype.split() with RegExp
    • String.prototype.replace() with RegExp
    • String.prototype.search with RegExp
    • String.prototype.match with RegExp
    • String.prototype.matchAll() and String.prototype.replaceAll()
    • Character classes (aka character sets)
    • Combining character classes
    • Negating character classes
    • Using the pipe for optional matching
    • Metacharacters
    • Regular expressions quantifiers
    • RegExp assertions
  • Chapter 13: Reflection and proxy objects (metaprogramming in JS)
    • The Reflect object
    • The Proxy object
    • Specifing a proxy handler object
    • An example of each trap method
    • Back to the Reflect object
    • Proxy (trap) invariants
    • Revocable proxies
    • Building a proxy of a proxy
  • Chapter 14: Web assembly objects
  • Chapter 15: Revision
    • 1. Build a new object and specify its prototype
    • 2. Copy enumerable own properties from one object to another
    • 3. Copy enumerable own properties from multiple objects into a single object
    • 4. Convert an array of arrays into an object
    • 5. Covert an object into an array of arrays
    • 6. Log out an object’s members as key-value pairs
    • 7. Inspect an objects own property descriptor(s)
    • 8. An alternative way of counting the number of members in an array
    • 9. Count the number of members in an associative array
    • 10. Find the number of own properties that an object has
    • 11. Get values out of an associative array
    • 12. On an object, add a named property with property descriptor editability
    • 13. On an object, add multiple named properties with property descriptor editability
    • 14. Prevent an object’s shallow properties from being deleted or changed (freeze an object)
    • 15. Freeze an array
    • 16. Prevent exensions of object’s properties but allow for deletions
    • 17. Prevent extensions and deletions of an object’s properties
    • 18. Define getters and setters on an object’s property
    • 19. Define getters and setters directly on an object literal
    • 20. Inspect getters and setters on an object’s specific property
    • 21. Check if an object has an own property and return a boolean of the result
    • 22. Check if an object’s own property’s property is enumerable
    • 23. Check if an object is a prototype of another object
    • 24. Call a method to check the number of arguments a function expects
    • 25. Log out all the arguments passed to a function call using the arguments array-like object
    • 26. Apply an object as the this value of another object’s method
    • 27. Pass arguments to a function using the apply() method without specifying the this argument
    • 28. Concatenate any number of arguments using the built-in “arguments” array-like variable
    • 29. Sum up any number of arguments using the built-in “arguments” array-like variable
    • 30. Concatenate the values of all the object’s properties, using another object’s joiner function
    • 31. Borrow Math.max() static method and apply it on an array of numbers to get the highest number
    • 32. Borrow Math.min() static method and apply it on an array of numbers to get the lowest number
    • 33. Use apply to monkey patch (extend) a built-in object as a polyfill on an older browser
    • 34. Borrow a method from one object to another object using call() without arguments
    • 35. Borrow a method from one object to another object using call() with arguments
    • 36. Use apply() instead of call() in a given code snippet
    • 37. Prove that every function call is calling the call() method in the background
    • 38. Chain constructors with the call() method
    • 39. Fix the problem of keeping the context of this in a nested function
    • 40. Why bind a function?
    • 41. Use bind() to cement the context of this
    • 42. Use bind() to partially apply a function
    • 43. Use bind() to pass context to setTimeout()
    • 44. Use bind() to make invocation shortcut on Array.prototype.slice()
    • 45. Set a symbol as an object’s key
    • 46. Add a symbol to an object literal
    • 47. Prove that each symbol is unique
    • 48. Check if a variable is of type symbol
    • 49. Log out a symbol’s description
    • 50. Why were symbols added to ES6?
    • 51. Get the value of a symbol key from an object
    • 52. Prove that symbols are excluded from for..in loops
    • 53. Add a symbol to an object without storing the symbol in a variable beforehand
    • 54. Prove that symbols are skipped in JSON conversion
    • 55. What will happen if we try to reassign an existing symbol property in an object
    • 56. Use a symbol to fix an ENUM list
    • 57. Show how to use a symbol as a metadata storage
    • 58. Show a use case for the Array[@@species] accessor
    • 59. Reimplement a “regular” iterator with Array.prototype[@@iterator]()
    • 60. Build an iterator that iterates over every even member of an array
    • 61. Build an iterator that iterates over every odd member of an array
    • 60. Convert a Set to an Array
    • 61. Use a mapping function with Array.from()
    • 62. Convert a string to an Array with Array.of()
    • 63. Iterate over an array with Array.prototype.entries
    • 64. Iterate over an array and break out of a loop based on a condition, using Array.prototype.entries
    • 65. Split an array into a series of arrays using Array.prototype.entries
    • 66. Split an array into a series of objects using Array.prototype.entries
    • 67. Push array keys into a separate array using Array.prototype.keys
    • 68. Print array values using Array.prototype.values
    • 69. Find index of a matching member of array or return -1 with Array.prototype.findIndex
    • 70. Search for a match from the end of array with Array.prototype.lastIndexOf
    • 71. Localize a decimal number as price with Array.prototype.toLocaleString
    • 72. Concatenate all args using Array.prototype.reduce
    • 73. Concatenate all args using Array.prototype.reduceRight
    • 74. How to throw errors in JS?
    • 75. How to catch errors in JS gracefully?
    • 76. How to customize error messages in JS?
    • 77. Show that the Promise() constructor must take a callback function
    • 78. Why no error is thrown when we call then() on a promise, without passing any functions to then()
    • 79. Build a promise that randomly fetches data from coindesk or throws an error, and catches it
    • 80. Display a message at the end of a promise regardless of whether it succeeds or fails
    • 81. Deal with potential errors by passing the second argument to the then() call in a promise
    • 82. “Promisify” a method that does not usually return a promise object
    • 83. Log out a sentence from inside a promise
    • 84. Send a notification of a promise successfully fulfilled
    • 85. Give an example of using Promise.reject()
    • 86. Give an example of using Promise.resolve()
    • 87. Return the GeneratorFunction() constructor
    • 88. Return the AsyncFunction() constructor
    • 89. Iterate values using Generator.prototype.next()
    • 90. Iterate an array using Generator.prototype.next()
    • 91. Send values to the generator
    • 92. Show that the Generator.prototype.return() finishes the generator

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