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JavaScript Fundamentals

When we talk about programming, the first thing that comes to mind is a set of instructions in a file. Source code is the text of a computer program in any programming language, a set of easy-to-read syntactic constructs outlining instructions for the program.

The source code cannot be understood by computers. However, there is post-programming action that converts the source code in a file into a set of instructions that computers can follow. This action is performed by a special program, compiler or interpreter. Therefore, the code is written not for machines, but for developers. Every source code should not only address a particular task, but also be understandable.

Logical thinking​

There are many programming languages in the world. They are not as complex as human ones, as they consist of a smaller set of syntactic constructs. Principles and basic concepts are similar between different programming languages.

Experienced developers think of problems in terms of algorithms, i.e. a set of steps that must be taken to achieve a goal. In our daily life, we use algorithms all the time. For example, the process of making tea consists of a number of steps (algorithm) to produce a result. When you get used to rely on algorithms for solving problems, any programming language will be just a tool.

JavaScript​

JavaScript is an implementation of the EcmaScript specification, a high-level programming language supported by all present-day web browsers. It was designed to deal with elements of web pages and add interactivity to them.

Note

JavaScript has nothing to do with the Java language. These are two independent programming languages.

In front-end development, JavaScript is used in conjunction with HTML and CSS to support the functionality of a web page, for example:

  • simple calculations;
  • checking and manipulating user-entered data;
  • storing information in the user's browser;
  • dynamically changing HTML documents;
  • reacting to user actions;
  • creating interactive elements: galleries, graphs, etc.;
  • interacting with the back end.
Note

When JavaScript code is written to run in a browser (front end), for security reasons the developer has neither tools nor access to the file system or operating system.

Today, using JavaScript you can create:

  • web applications using frameworks such as React, Vue, Angular and others;
  • back-end applications using Node.js;
  • mobile applications with React Native or Ionic;
  • desktop applications using Electron;
  • microcontrollers with Johnny-Five and Espruino.

Using all these options requires the knowledge of programming syntax; the features and mechanisms of a particular language; as well as algorithmic thinking and experience in practical problem solving.