GreenComet - Notes from a web programmer

There are several ways to create objects in JavaScript . The Object data type plays a critical role in JS . An object is an unordered set of key-value pairs. May contain other objects 1. Literal notation var someObject_1 = {}; Perhaps the most common and easiest way. Let's add properties and methods someObject_1.name = "John"; someObject_1.age = 25; someObject_1.run = function(){ console.log("run") } And now the same thing, but we will set properties and methods when creating var someObject_1 = { name: "John", age: 25, run: function(){ console.log("run"); } }; 2. Object constructor This method is not recommended for use, and it is better to use the previous one. Nevertheless, it exists. But the probability of meeting him is extremely small var someObject_2 = new Object(); We also set properties and methods var someObject_2 = { name: "Nick", age: 30, jump: function(){ conso

HTTPS is an advanced data transfer protocol that supports encryption. Install free ssl certificate from Lets Encrypt . Ubuntu server operating system Get a certificate sudo letsencrypt certonly -a webroot --webroot-path=/var/www/site.com/public_html -d site.com -d www.site.com Prolong sudo letsencrypt renew nginx config server { listen 80 ; server_name site.com.ru www.site.com; return 301 https://$server_name$request_uri; } server { # SSL configuration listen 443 ssl http2; listen [::]:443 ssl http2; server_name site.com www.site.com; ssl_certificate /etc/letsencrypt/live/site.com/fullchain.pem; ssl_certificate_key /etc/letsencrypt/live/site.com/privkey.pem; ssl_trusted_certificate /etc/letsencrypt/live/site.com/chain.pem; add_header Content-Security-Policy "img-src https: data:; upgrade-insecure-requests"; # We keep access log: access_log /var/log/nginx/site.com_access.log; # We share static and dynamic, static

Sometimes it becomes necessary to limit the number of queries to an external data source. Especially if they do not change constantly. For example, the exchange rate in the central bank. Or simply speed up the page loading, giving the script an already generated file. $expires = 3600; //Cache lifetime in seconds $curTime = time(); $cacheFile = 'data.json'; function writeCache($cacheFile) { //get fresh data file_put_contents($cacheFile, file_get_contents('http://somesite.com/api')); } if (!file_exists($cacheFile)) { writeCache($cacheFile); } else { $fMtime = filemtime($cacheFile); if (($curTime - $fMtime) > $expires) { writeCache($cacheFile); } } This caching method is based on comparing the date of the file change with the cache with the current time.

Consider uploading files to a PHP server using the POST method. This will require a form with the file field type and an enctype attribute with a multipart/form-data value. HTML <form method="POST" enctype="multipart/form-data"> <input type="hidden" name="MAX_FILE_SIZE" value="2097152" /> <input type="file" name="uploaded_file"> <input type="submit" name="submit" value="send"> </form> The field with name="MAX_FILE_SIZE" must be placed above the input type="file" , the value is set in bytes. The field is optional and the check must be still on the server. After sending the data of the uploaded file get into the $_FILES array if(isset($_FILES["uploaded_file"])){ //field´s name type="file" $maxsize = 1024 * 1024* 2; //limited the allowed file size to 2 MB $errors = []; //valid file exten

The file is written for Gulp 4 . The file is designed to work with styles ( SCSS ) and JavaScript . All minify and compile sourcemaps for debugging. Third-party scripts and styles are in separate files. const production = ( process.env.NODE_ENV == 'production' ); //base part let {src, dest, parallel, series, watch} = require('gulp'), rename = require('gulp-rename'), sourcemaps = require('gulp-sourcemaps'); //css part let sass = require('gulp-sass'), cleanCSS = require('gulp-clean-css'), autoprefixer = require('gulp-autoprefixer'); const babel = require('gulp-babel'), uglify = require('gulp-uglify-es').default, include = require("gulp-include"); let pathFiles = { build: { css: './css/', js: './js/' }, src: { css: './src/scss/**/*.scss', js: './src/js/**/*.js' } }; function swallowError(error){

In many programming languages implemented inheritance. And it also exists in JavaScript. First, consider prototype inheritance. We describe the function constructor function Animal(name, weight, color){ this.name = name || 'someAnimal'; this.weight = weight; this.color = color; //do some actions during initialization console.log(this.name + ' construct animal'); } // write the method to the prototype Animal.prototype.sayName = function(){ console.log(this.name); } We describe the constructor function that inherits the Animal class. And we will expand it, we will add in addition own properties and methods function Mammal(name, weight, color, limbs){ Animal.apply(this, arguments); this.limbs = limbs || 4; console.log(this.name + ' construct mammal'); } Mammal.prototype = Object.create(Animal.prototype); Mammal.prototype.constructor = Mammal; Mammal.prototype.run = function(){ console.log('run'); } Cre