kaiguogit

const { rxObserver } = require('api/v0.3');
const { timer, combineLatest } = require('rxjs');
const { take, filter } = require('rxjs/operators');


const a$ = timer(0, 10).pipe(
    take(5)
  );

const b$ = timer(0, 4).pipe(

kaiguogit

tmux cheat sheet

(C-x means ctrl+x, M-x means alt+x)

Prefix key

The default prefix is C-b. If you (or your muscle memory) prefer C-a, you need to add this to ~/.tmux.conf:

remap prefix to Control + a

kaiguogit

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

kaiguogit

var response={ 
  authors:[
    {
      id: 1,
      name: "Monica",
      posts: [
        {
          id: 1,
          title: "how to write fast js",

kaiguogit

Q: Why don't have to write conditional statement to determine whether input is object or array? A: because Object.keys behave similarly when input is input or object, It returns an array of index when input is an array. See below example from MDN doc.

var arr = ['a', 'b', 'c']; console.log(Object.keys(arr)); // console: ['0', '1', '2']

kaiguogit

1.
  Q: A function doesn't have to return in order to be called a closure. Simply accessing variables outside of the immediate lexical scope creates a closure.
  A: Nested functions, inner function access the outer function's variable. Then it's a closure, whether or not it return the variable to make it accessible outside.
2. 
  Q:function getMaxOfArray(numArray) {
  return Math.max.apply(null, numArray);
}
  A: This apply method takes an array as argument instead of argument list, so that we can use an array like object as argument.
  getMaxOfArray([1,2,3]) instead of Math.max(1,2,3)
3. 

kaiguogit

Q: How do you think the word "cascading" in "Cascading Style Sheets" relates to specificity?

A: Cascading means while multiple rules applies to one element, the more specific rule override general rule. The latest applied rule override rules applied earlier.

Q: text in h1 is blank A:

1. There could be another style sheet applied later, (or closer) to the element that override the style

kaiguogit

function arrayOfLight(number){
  var a = [];
  for(i=0; i<=number; i++){
    a.push(i);
  }
  return a;
}

kaiguogit

--Exercise 1
--Fetch ISBN of all book editions published by the publisher "Random House". You should have 3 results.
SELECT e.isbn 
FROM editions AS e 
  JOIN publishers AS p ON (e.publisher_id = p.id) 
WHERE p.name = 'Random House';

--Exercise 2 
--Instead of just their ISBN number, fetch their Book Title as well. You should still have the same 3 results but with more information. But instead of just one column, we should have 2 columns in the result set.
SELECT e.isbn, b.title 

kaiguogit

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