JackNavaRow's questions

Throughout learning Javascript, I've read terminologies like Shallow Copy and Deep Copy , and the following question came up:

What is the real difference between Shallow Copy and Deep Copy ?

const moderador = {
  nombre : "Gbianchi", 
  lenguajesFavoritos : ["JavaScript", "Java","PHP"],
  esDesarrollador : true, 
  fechaNacimiento : "2010/01/01"
}

const persona = Object.assign({}, moderador);
persona.nombre = "PabloLozano"
persona.esDesarrollador = false;
persona.lenguajesFavoritos.push("PHP7");

console.info("moderador", moderador );

console.info("persona", persona)

When I try to make a request GET, POST, PUT, PATCH,DELETE from my Frontend I receive from the server

Request from another origin blocked: Same origin policy prevents reading remote resource at http://my_server/ (reason: missing CORS 'Access-Control-Allow-Origin' header).

I have also seen it in English something like:

"No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access."

I've researched WHAT CORS is and the W3C comments on this topic , and I understand what Cross-Origin Resource Sharing means , but I don't understand how it works.

How could I solve this in my WEBS applications?

Finally, I have noticed that my front-end applications generally make two requests, one of type OPTIONSand the common ones [ GET, POST, PUT, PATCH....] this is because

I do the tests with test-cors.org and it gives me the same error

Reading the question how to display data in a JSON , add a comment about how to display it using the console.table, What other features does the console have.

In the following example I have a class and add two functions by prototype , the first one as defined funcion normalmente, while the second one witharrow function

simpleClase = function(){
  this.ejemplo = 1
}
simpleClase.prototype.simple = function(){
  console.log(this)
}
simpleClase.prototype.arrow = () =>{
console.log(this)
   }
 
let nuevaClase = new simpleClase();
nuevaClase.simple();
nuevaClase.arrow();

The case is that for the function as normally defined with prototype it returns me the contexto de la clase, while using arrow functionit returns mewindow

With another Example:

class Clase  {
  constructor(){
  this.valor = 1

  }
  arrow() {
    let miFuncion= () => console.log("arrow" , this);
    miFuncion();
  }
  simple(){
    console.log("simple" , this);
  }
}
let miClase = new Clase();
miClase.arrow()
miClase.simple()

It returns the context of the class, this gives me the doubt of how prototype works with the arrow function , my doubt is because these scopes are different, because the prototype does not take the scope of the variable

Download to the server with the following command

git clone --branch tag_1 mi_url

but they asked me to install the tag_2, check the tags that are found by executing the command

git tag -l

I got the list of tag and if it was, my question is how do I do one git pullthat only downloads the version tag_2, and if so, do you know any command where you can see that tagit is installed in the repository

I have a database that is constantly growing, so I must take great care of these records.

I was looking on the internet and Oracle Corporation (owner of MySQL since 2010) provides a paid product, MySQL Enterprise Backup , to perform this type of backup with one command, mysqlbackups.

An example of use:

mysqlbackup --backup-image=/backups/sales.mbi --backup-dir=/backup-tmp backup-to-image

With this tool there is a way to perform incremental backup and perform differential backup.

My question basically is: How to perform an incremental or differential backup with basic MySQL commands?