Promise

Events

Event manager

Write event emitter-base class that allows you to add event listeners

https://netbasal.com/javascript-the-magic-behind-event-emitter-cce3abcbcef9

Custom events

Events can be created with the Event constructor as follows:

let event = new Event(type[, options]);

Debounce

Throttling

Reference

https://javascript.info/dispatch-events

Closure

Currying

Borrowing

sum(a, b)/ sum(a)(b)

Caching

Once method (implement a function that can be called only once)

Arrays, Objects, and Strings are commonly used types that we iterate using ‘for’. ‘for…in’, ‘for…of’ statements.

Array iteration

1. for

Repeats until a specified condition evaluates to false.

for ([init]; [condition]; [increment])

“All the three blocks in the for loop can be omitted. But should be declared before.”

2. for…of

for (variable of iterable)

“Iterable can be ‘Array, String, array-like objects, TypedArray, Map, Set and user-defined iterables”.

Use the below code to test whether the object is iterable or not:

typeof obj[Symbol.iterator] === 'function'; // 'obj' will be the var

Don’t use for..in loop for arrays. It iterates over both array…

Functions

Recursive function example 1 — factorial

Recursive function example 2 — Fibonacci

Recursive function example 3 — Decimal to binary conversion

Pascal triangle

I liked the below reference to generate the pascal triangle one row at a time using 2 functions:https://medium.com/javascript-in-plain-english/algorithms-101-pascals-triangle-in-javascript-9fbd9032871

Strings coding questions and answers

String Reverse

Reverse Words

Palindrome

Anagram

Isomorphic

Given a sentence, “Hello how are you HELLO”. Find the minimum distance between two words. Given input: hello, you. Output: 1. The input words are case insensitive (levenshteinDistance (s, t))

https://en.wikibooks.org/wiki/Algorithm_Implementation/Strings/Levenshtein_distance

Objects

Check is given two objects are equal

https://dmitripavlutin.com/how-to-compare-objects-in-javascript/
https://www.samanthaming.com/tidbits/33-how-to-compare-2-objects/

Extending object/ object deep clone

Array related questions and answers from brute force to better optimal way of achieving Big O

Find the maximum value of an array

Remove duplicate from an array/ unique array

Get duplicates from an array

Flatten the array

Find the median value of an array

Find two sum of an array twoSum(arr, sum)

Maximum consecutive sum of integers in an array

Union of arrays (merge two arrays without duplicates)

Intersection of arrays/ find common values of arrays (multidimensional)

Given an array of integers, every element appears twice except for one. Find that single one

Given an array of integers, find the largest product yielded from three of the integers

Being told that an unsorted array contains (n — 1) of n consecutive numbers (where the bounds are defined), find the missing number in O(n) time

Given an array of integers, find the largest difference between two elements such that the element of lesser value must come before the greater element

Given an array of integers, return an output array such that output[i] is equal to the product of all the elements in the array other than itself. (Solve this in O(n) without division)

DNF problem (An array just contains 1s, 2s, and 3s. Sort the array)