Web Technologies

JavaScript Hoisting

Posted on by admin

This topic is very very important in javaScript. It is an unknown behavior of javaScript. Shortly, javaScript compiler moves variables and function declarations

Hoisting is JavaScript's default behavior of moving declarations to the top of the current scope.

Variables and constants declared with let or const are not hoisted!

JavaScript Declarations are Hoisted

In JavaScript, a variable can be declared after it has been used.

In other words, a variable can be used before it has been declared.

Hoisting applies to variable declarations and to function declarations.

function declarations are hoisted before variable declarations.

Hoisting is only possible with declaration but not the initialization. JavaScript will not move variables that are declared and initialized in a single line.

Continue reading →

JavaScript Functions

Posted on by admin

I sometimes try to remember basis of JavaScript Functions. So, I often exercise about it. I followed this link https://www.w3schools.com/js/js_function_definition.asp. I copied some important descriptions from that link. My aim is to follow this post when I need to remember again 🙂

JavaScript Functions

A JavaScript function is a block of code designed to perform a particular task.

A Function is much the same as a Procedure or a Subroutine, in other programming languages.

Why Functions?

You can reuse code: Define the code once, and use it many times.

You can use the same code many times with different arguments, to produce different results.

JavaScript Function Types

  1. Function Declaration (function statement)
  2. Function Expression
  3. Function Constructor
  4. Self-Invoking Function (Immediately Invokable Function Expression IIFE)
  5. Arrow Function
  6. Object Method Shorthand Definition
  7. Generator Function
Continue reading →

Node.js Babel 6.x different usage transpiling to ES5 and Debugging

Posted on by admin

There are different usages of babel tool. I put a sample package.json file. Notice that there are scripts block which has different usages.

You can reach github project from the following link.

https://github.com/kenanhancer/babel6-usage.git

You can reach Babel 7.x post from the following link.

Node.js Babel 7.x different usage transpiling to ES5 and Debugging

Creating Babel configuration file

.babelrc

{
  "presets": [
    "env"
  ],
  "plugins": [
    "transform-runtime"
  ],
  "sourceMaps": true,
  "retainLines": true
}

Running with Babel-node

//If you have installed babel-cli package globally, run below code.
babel-node --presets=env --plugins=transform-runtime src

or

//If you have .babelrc config file, run below code without specifying inline arguments.
babel-node src

or

//If you have installed babel-cli package locally, run below code.
./node_modules/.bin/babel-node --presets=env --plugins=transform-runtime src
Continue reading →

Node.js Module Export and Import with CommonJS and ES6

Posted on by admin

I hope that this post will help any developer who need to see variations of importing and exporting modules. To be honest, due to using different programming languages, I sometimes forget some features so this post helped me every time 🙂

This is an other online code editor. Same examples is in this example as well.

CJS and ESM Usage Demo