Goal:

To improve your understanding of JavaScript syntax, functions, and higher-order functions, and to better understand JavaScript and Array methods.

Assignment:

The following (12) are some of the most popular and used methods in functional languages:

• forEach
• Map
• Filter
• Some (Any)
• Every
• Reduce
• Includes
• indexOf
• Push
• lastIndexOf
• Object.keys()
• Object.values()

For this assignment, you will recreate these methods using JavaScript functions. Make sure to carefully understand what each method is designed to do, and DO NOT use any of the respective native JS methods to implement your solutions. Also, keep in mind that these methods do not (except for push()) mutate the input array. We highly suggest utilizing Mozilla Developer Network (MDN) Web Docs to understand how each method works and what arguments they take. Also look into Array.prototype.pop(), Array.prototype.shift(), and other methods for your own enrichment.

forEach()

Without using the native Array.prototype.forEach method of JavaScript, compose a function titled myEach that will take in an array of elements and executes any callback function (provided by you) on each of those elements.

map()

Without using the native Array.prototype.map method of JavaScript, compose a function titled myMap that will take in an array of elements and executes a callback function (provided by you) on each of those elements.

filter()

Without using the native Array.prototype.filter method of JavaScript, compose a function titled myFilter that will take in an array of elements and executes a callback function (provided by you) on each of those elements.

some() (aka any())

Without using the native Array.prototype.some method of JavaScript, compose a function titled mySome that will take in an array of elements and executes a callback function (provided by you) on each of those elements.

every()

Without using the native Array.prototype.every method of JavaScript, compose a function titled myEvery that will take in an array of elements and executes a callback function (provided by you) on each of those elements.

reduce()

Without using the native Array.prototype.reduce method of JavaScript, compose a function titled myReduce that will take in an array of elements and executes a callback function (provided by you) on each of those elements.

includes()

Without using the native Array.prototype.includes method of JavaScript, compose a function titled myIncludes that will take in an array of elements and indicates whether or not a target element is contained within the input array. This returns a boolean.

indexOf()

Without using the native Array.prototype.indexOf method of JavaScript, compose a function titled myIndexOf that will take in an array of elements and returns the index of the first encounter of a target element (if it is found) or -1 if that element does not exist within the input array.

push()

Without using the native Array.prototype.push method of JavaScript, compose a function titled myPush that will take in an array of elements as well as an elementToAdd and append that element to the end of the array.

lastIndexOf()

Without using the native Array.prototype.lastIndexOf method of JavaScript, compose a function titled myUnshift (typo) that will take in an array of elements and returns the index of the last encounter of a target element (if it is found) or -1 if that element does not exist within the input array.

Object.keys()

Without using the native Object.keys() method of JavaScript, compose a function titled grabKeys that will take in an object and return all of the keys of the key:value pairs of that object. Modify the Object class, appending a static method to the Object class., appending a static method to the Object class. Leverage the for...in loop.

Object.values()

Without using the native Object.values() method of JavaScript, compose a function titled grabValues that will take in an object and return all of the values of the key:value pairs of that object. Modify the Object class, appending a static method to the Object class. Leverage the for...in loop.

Miscellaneous Problems (4)

From Chapter 4 of Eloquent JavaScript

• Sum of a Range
• Reversing an Array
• A List
• Deep Comparison

Miscellaneous Problems (1)