zjkuang

zjkuang Zhengqian (John) Kuang iOS Developer Regina, SK, Canada

Keybase proof

I hereby claim:

• I am zjkuang on github.
• I am zjkuang (https://keybase.io/zjkuang) on keybase.

zjkuang

//
//  CombineCheatSheet.swift
//  
//
//  Created by Zhengqian Kuang on 2020-05-17.
//

import Foundation
import Combine

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// TypeScript Playground - https://www.typescriptlang.org/play

////////////////////////////////////////////////////////////////////////////////

// Start multiple promises simultaneously and execute them in parallel

const p1 = new Promise((resolve) => {
    setTimeout(() => {
        const result = Date();
        console.log(`r1: ${result}`);

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function anyToString(a: any): string {
  if (Array.isArray(a)) {
    let s = '[';
    const arr = a as Array<any>;
    const numberOfElements = arr.length;
    arr.map((e, index) => {
      let eString = anyToString(e);
      s = s + eString;
      if (index + 1 < numberOfElements) {
        s = s + ',';

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Visual Representation of SQL Joins
  https://www.codeproject.com/Articles/33052/Visual-Representation-of-SQL-Joins

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Sophie's Maths

In Terminal, npx <url-of-this-gist>

IMPORTANT: If you have made any changes in the script, to make the changes visible, make sure you update the version number in package.json

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In Termial, run

npx <url-of-this-gist>

Each time you make any change, remember to update the version in package.json

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// Consider the "smallest" positive number in JavaScript, (where there are 322 zeros before "1" after the point,)
const a  = 0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001;
// I call it "smallest" because if we add one more zero before the "1", JavaScript takes it as zero:
const a0  = 0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001;
console.log(`a0 == 0: ${a0 == 0}`); // true

// Now let's check a number b9,
// a  = 0.0...01  // 0.(322 zeros)1
// b9 = 0.0...009 

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// [1]
// [1,1]
// [2,1]
// [1,2,1,1]
// [1,1,1,2,2,1]
// [3,1,2,2,1,1]
// [1,3,1,1,2,2,2,1]
// [1,1,1,3,2,1,3,2,1,1]
// [3,1,1,3,1,2,1,1,1,3,1,2,2,1]
// [1,3,2,1,1,3,1,1,1,2,3,1,1,3,1,1,2,2,1,1]