kevinwucodes

This problem was recently asked by Google.

Given a list of numbers and a number k, return whether any two numbers from the list add up to k.

For example, given [10, 15, 3, 7] and k of 17, return true since 10 + 7 is 17.

function isAddedNumberInArray(inputAry, n) {
  return (
    inputAry

kevinwucodes

This problem was asked by Uber.

Given an array of integers, return a new array such that each element at index i of the new array is the product of all the numbers in the original array except the one at i.

For example, if our input was [1, 2, 3, 4, 5], the expected output would be [120, 60, 40, 30, 24]. If our input was [3, 2, 1], the expected output would be [2, 3, 6].

function aryTransform(input) {

kevinwucodes

--https://stackoverflow.com/questions/31211506/how-stuff-and-for-xml-path-work-in-sql-server
--https://stackoverflow.com/questions/273238/how-to-use-group-by-to-concatenate-strings-in-sql-server

;with colors as (
	select id, name, color
	from (
		values
			 (1, 'kevin', 'blue')
			,(2, 'kevin', 'red')
			,(3, 'aria', 'pink')

kevinwucodes

;with names as (
	select name, color
	from (
		values
			 ('kevin','blue')
			,('kevin','blue')
			,('kevin','red')
	) x (name, color)
)
select 

kevinwucodes

--;with q as (
--	select id, color, intensity
--	from (
--		values
--			 (1,'blue',4)
--			,(2,'red',5)
--			,(3,'blue',7)
--			,(4,'blue',1)
--			,(5,'yellow',3)
--	) colors (id, color, intensity)

kevinwucodes

select

ranked = case
	when color <> 'black' then
		row_number() over (partition by
			case when color <> 'black' then 1 end			
			,person
			order by (select null)
		)
	else null

kevinwucodes

;with persons as (
	select id, name, gender, color
	from (
		values
			 (1,'kevin','m','blue')
			,(2,'owen','m','blue')
			,(3,'wendy','f','pink')
			,(4,'emrys','m','black')
			,(5,'aria','f','brown')
	) q (id, name, gender, color)

kevinwucodes

Today, I got stumped. Let's get unstumped.

While watching André Staltz's excellent Two Fundamental Abstractions talk, he shared something like this about 24 minutes into his talk:

const a = b => b(10)

a(x => console.log(x))

kevinwucodes

page.evaluate

const a = await page.evaluate(selector => document.querySelector(selector).textContent, WELCOMETAG_SELECTOR)

page.$eval

const b = await page.$eval(WELCOMETAG_SELECTOR, stuff => stuff.textContent)

kevinwucodes

Ways to use debounce in React

In Constructor

inspired by: http://blog.revathskumar.com/2016/02/reactjs-using-debounce-in-react-components.html

class Test extends React.Component {
  constructor(props) {
    super(props)