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This article mainly shows you "what are the basic concepts in JavaScript". The content is simple and clear. I hope it can help you solve your doubts. Let the editor lead you to study and learn this article "what are the basic concepts in JavaScript".

For beginners, Javascript seems easy at first glance because its syntax is similar to that of C.

No matter how it works, the constant changes to the language (ESNext) and its framework may overwhelm beginners.

I'm here to dispel the confusion surrounding what I think is a beautiful but most important language.

It's lucrative because JS can easily do almost anything you want to do today.

Want to build a Web application? No problem.

Want to build CLI tools? No problem.

Want to build desktop applications? Poof. It's easier done than said!

The increasing number of packages and libraries provided every day shows how abstract JS is when building software applications.

However, JS seems to be hated by many people, mainly because of how unconventional it is compared to its competitors. Anyone who might miss out on JS theory will be confused.

Many people ignore the theoretical aspects of Javascript before delving into Javascript. These concepts help us understand the different paths and patterns used to build Javascript applications. These patterns exist in every framework of JS Land, so it makes sense to understand these concepts before learning the language itself.

The characteristics of JS (1) multiple paradigms

Javascript supports procedural, object-oriented, and event-driven functional programming!

Mastering the object-oriented programming style of JS can prove very useful.

Object-oriented programming can help programmers more easily visualize the components of software applications.

In addition, learning Typescript (Javascript with Types) makes it easy for programmers to implement the best design patterns in the industry. These design patterns are used to solve the most common problems encountered in software programming in the most effective way.

This versatility makes Javascript very approachable, but also very powerful.

(2) explanation

Javascript is different from C _ innate +, where the program is not read once, but is interpreted line by line. This means that JS will be slower than compiled languages such as CAccord Cure +.

Warning: Javascript is notorious for being a very passive language at runtime. It is very difficult to troubleshoot errors.

But don't lose heart. With time and practice, you will learn how to sail comfortably. The most common error involves your variable returning a null value. When such problems do occur, please go to Stack Overflow, because I assure you that no matter how small the mistake is, you will not be the first person to encounter it. However, it is always a good idea for console.log () to use it freely while your project is under development. This can help you pinpoint the moments in the program's life cycle, and your variables may have fallen off.

(3) single thread

Javascript can only perform one task at a time. It queues different tasks to different queues according to the type.

In the most abstract sense, Javascript basically groups synchronous and asynchronous tasks and queues them separately.

Synchronization tasks are statements that are processed immediately when they are encountered, that is, they run immediately. These tasks include log statements, variable declarations, conditional checks, and so on.

Asynchronous tasks involve tasks that may require variable time to return output. An example of an asynchronous task might be to request information from Web API.

In addition, Javascript has a Job Queue for processing a JS Feature named Promises.

You can actually see the single-threaded nature of Javascript by right-clicking the page and clicking the check tab. Next, go to the console tab on the window you just opened. Enter the following code and press enter.

While (true) {}

You can now observe that this page is completely unresponsive. This is because the Javascript on this page is now busy running the infinite while loop we executed above.

(4) non-blocking

We've talked about asynchronous tasks before. Because JS runs in a single-threaded environment, by default, it doesn't wait for anyone!

Asynchronous code blocks are executed only after all synchronous code blocks have been executed, regardless of the location of the code in the program.

Console.log ("I'm the first statement") setTimeout (() = > {console.log ("I'm the second statement")}, 1000) console.log ("I'm the third statement")

Here console.log () records the statements in it to the console.

The above setTimeout () function runs the second statement after a second.

When checking the output

I'm the first statementI'm the third statementI'm the second statement

We can see that the third statement is recorded before the second statement. This is because of JS's inherent way of handling synchronous and asynchronous blocks of code.

(5) High-level

JavaScript is a high-level language. High-level languages may simply mean that they are closer to the language spoken by humans. High-level languages can provide more functionality to help programmers better express what they are trying to build.

This advanced feature of Javascript helps it best serve the client part of Web. One of the main limitations of JS in the past was that it could only provide services on the client side and could not manipulate files like most server-side languages.

However, this has changed NodeJS to allow developers to use Javascript to build back-end servers. Therefore, software developers can operate on both the server side and the client side by using only one language. This causes the full stack engineer to become prominent.

(6) dynamic type

Javascript is a dynamically typed language. This means that unlike C, which needs to specify a data type for a variable, we can use type-inference in Javascript to automatically detect the type of data, and the variable is saved.

/ / In C variables must have datatypes. In order to change datatypes from one type to / / another, we need to use type-castingint a = 5Tracchar b = "a"; float c = 7.036

In Javascript, we use let and const to declare variables or constants, respectively.

Let a = 5console.log (a) / / 5a = 'Hello World'console.log (a) / / Hello Worldconst b =' JS is awesome' console.log (b) / / JS is awesomeb ='I changed my mind'console.log (b) / / Error: const cannot be changed

Although type inference looks like a bonus point because it is easy to use, it immediately becomes a hoax for large projects that require type safety as a feature.

For this reason, larger projects use TypeScript, which is just a wrapper for Javascript, providing types, interfaces, and various other features.

Learning strategies

It takes a while to settle down in JS Land, but I have a simple list of Minimum Requirements for learning frameworks such as Express or ReactJS.

First of all, don't rush to learn these frameworks. Take some time to master Vanilla Javascript.

Basic knowledge

Variables and constants

Conditional block (if-else)

Loops (for, while, forEach)

Switch box

Function

These are essential programming foundations.

Advanced part (minimum requirement)

Async / wait

Promise

Classes in Javascript

Rest / spread grammar

Array / object iterator

Array deconstruction

Module (import, export)

These are all the contents of the article "what are the basic Concepts in JavaScript". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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