Wing Leung wingleungchoi

Sync Pool is a tool to reuse memory allocations . and it can be shared among different threads.

Reducing time of memory allocation

Based on the example, when we create a large struct, it will require more memory allocation
- ref: https://www.youtube.com/watch?v=rfXSrgIGrKo
- ref: https://github.com/campoy/justforfunc/tree/master/37-sync-pool
Sync Pool can enable us to reuse the struct i.e. reuse the memory and reduce memory allocation

I am new to terraform and AWS networking. I have the following tips. Hope people may find them useful.

Draw your AWS Architecture Diagram
- which provides an anchor and north star during builing your infrastructure
Need to create internet gateway for new created VPC.
- It is because default VPC in AWS comes with default internet gateway.
- but new created VPC does not have default internet gateway.
Need to create NAT gateway for resources (e.g. ec2) in private subnets to access internet (egress traffic)
- note: egress traffic means internet requests FROM the resources
Need to create security group for resources in private subnet

	This is my basic understanding of frontend JS framework. Feel free to comment it.


	Javascreipt Framework help you build a "responsive" website.
	Traditionaly, the sever will give a response which consist of Webpages(HTML + CSS), assets(Images, video, sounds...) + JavaScript when browser send a requests.

	There is a new way to communicate between browser and sever by using AJAX. Instead of bulks of data, sever will give a response in XML or JSON( a text format). Once browser get and load it, it will update the existing page rather than regenerate a webpage from null.

	Responding in format of JSON is breakthrough. Base on a new communication, Using a JavaScript can create a website is responsive and dynamic in frontend and possible to skip backend if you just use third parties API and no backend code is written by yourself.

	public class Dog {
	// Attributes [i.e. data]
	private String name;
	// Behavior [i.e. methods]
	// Constructors
	public Dog() //constructor which takes no parameters, sets to default
	{
	name="";
	}
	// fully parameterized constructor

	class Dog {
	constructor(nameOrDog = '') {
	if (nameOrDog instanceof Dog) {
	this.name = nameOrDog.getName();
	} else if ((typeof nameOrDog) === 'string') {
	this.name = nameOrDog;
	} else {
	// throw new Error('type is not supported');
	}
	}

	Six basic types of values in JavaScript: numbers, strings, Booleans, objects, functions, and undefined values.

	JavaScript is a very free language. It tries to converse the type of a value to another type. There are pros and cons. Pros: more flexible a code can be. Cons: more errors a code can have.

	As a beginner, prefer === rather than ==