JavaScript Keycode List – Keypress Event Key Codes for Enter, Space, Backspace, and More

JavaScript keyboard events help you capture user interactions with the keyboard.

Like many other JavaScript events, the KeyboardEvent interface provides all the required properties and methods for handling every keystroke a user makes using the keyboard.

There have been many articles written about how they work and how to use them. At the same time, W3.org keeps updating the specification by introducing new properties, deprecating existing ones, and marking certain code as legacy.

Because of this, it is essential for web developers to keep learning about the KeyboardEvent interface to know what exactly they should use and what’s no longer relevant.

In this article, we will learn about:

• The KeyboardEvent interface.
• The keyboard event types we need to focus on.
• The keyboard event types we may not ever need.
• Which properties you need in practice and how different browsers handle them.
• What is deprecated, and what’s in use.
• A playground to try things out as we learn.
• Finally, the current list of key codes for reference and future use.

Hope you enjoy it.

#javascript #programming #developer #web-development

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JavaScript Keycode List – Keypress Event Key Codes for Enter, Space, Backspace, and More

JavaScript keyboard events help you capture user interactions with the keyboard.

Like many other JavaScript events, the KeyboardEvent interface provides all the required properties and methods for handling every keystroke a user makes using the keyboard.

There have been many articles written about how they work and how to use them. At the same time, W3.org keeps updating the specification by introducing new properties, deprecating existing ones, and marking certain code as legacy.

Because of this, it is essential for web developers to keep learning about the KeyboardEvent interface to know what exactly they should use and what’s no longer relevant.

In this article, we will learn about:

• The KeyboardEvent interface.
• The keyboard event types we need to focus on.
• The keyboard event types we may not ever need.
• Which properties you need in practice and how different browsers handle them.
• What is deprecated, and what’s in use.
• A playground to try things out as we learn.
• Finally, the current list of key codes for reference and future use.

Hope you enjoy it.

#javascript #programming #developer #web-development

What is JavaScript - Stackfindover - Blog

Who invented JavaScript, how it works, as we have given information about Programming language in our previous article ( What is PHP ), but today we will talk about what is JavaScript, why JavaScript is used The Answers to all such questions and much other information about JavaScript, you are going to get here today. Hope this information will work for you.

Who invented JavaScript?

JavaScript language was invented by Brendan Eich in 1995. JavaScript is inspired by Java Programming Language. The first name of JavaScript was Mocha which was named by Marc Andreessen, Marc Andreessen is the founder of Netscape and in the same year Mocha was renamed LiveScript, and later in December 1995, it was renamed JavaScript which is still in trend.

What is JavaScript?

JavaScript is a client-side scripting language used with HTML (Hypertext Markup Language). JavaScript is an Interpreted / Oriented language called JS in programming language JavaScript code can be run on any normal web browser. To run the code of JavaScript, we have to enable JavaScript of Web Browser. But some web browsers already have JavaScript enabled.

Today almost all websites are using it as web technology, mind is that there is maximum scope in JavaScript in the coming time, so if you want to become a programmer, then you can be very beneficial to learn JavaScript.

JavaScript Hello World Program

In JavaScript, ‘document.write‘ is used to represent a string on a browser.

<script type="text/javascript">
	document.write("Hello World!");
</script>

How to comment JavaScript code?

• For single line comment in JavaScript we have to use // (double slashes)
• For multiple line comments we have to use / * – – * /

<script type="text/javascript">

//single line comment

/* document.write("Hello"); */

</script>

Advantages and Disadvantages of JavaScript

#javascript #javascript code #javascript hello world #what is javascript #who invented javascript

Static Code Analysis: What It Is? How to Use It?

Static code analysis refers to the technique of approximating the runtime behavior of a program. In other words, it is the process of predicting the output of a program without actually executing it.

Lately, however, the term “Static Code Analysis” is more commonly used to refer to one of the applications of this technique rather than the technique itself — program comprehension — understanding the program and detecting issues in it (anything from syntax errors to type mismatches, performance hogs likely bugs, security loopholes, etc.). This is the usage we’d be referring to throughout this post.

“The refinement of techniques for the prompt discovery of error serves as well as any other as a hallmark of what we mean by science.”

• J. Robert Oppenheimer

Outline

We cover a lot of ground in this post. The aim is to build an understanding of static code analysis and to equip you with the basic theory, and the right tools so that you can write analyzers on your own.

We start our journey with laying down the essential parts of the pipeline which a compiler follows to understand what a piece of code does. We learn where to tap points in this pipeline to plug in our analyzers and extract meaningful information. In the latter half, we get our feet wet, and write four such static analyzers, completely from scratch, in Python.

Note that although the ideas here are discussed in light of Python, static code analyzers across all programming languages are carved out along similar lines. We chose Python because of the availability of an easy to use ast module, and wide adoption of the language itself.

How does it all work?

Before a computer can finally “understand” and execute a piece of code, it goes through a series of complicated transformations:

As you can see in the diagram (go ahead, zoom it!), the static analyzers feed on the output of these stages. To be able to better understand the static analysis techniques, let’s look at each of these steps in some more detail:

Scanning

The first thing that a compiler does when trying to understand a piece of code is to break it down into smaller chunks, also known as tokens. Tokens are akin to what words are in a language.

A token might consist of either a single character, like (, or literals (like integers, strings, e.g., 7, Bob, etc.), or reserved keywords of that language (e.g, def in Python). Characters which do not contribute towards the semantics of a program, like trailing whitespace, comments, etc. are often discarded by the scanner.

Python provides the tokenize module in its standard library to let you play around with tokens:

Python

1

import io

2

import tokenize

3

4

code = b"color = input('Enter your favourite color: ')"

5

6

for token in tokenize.tokenize(io.BytesIO(code).readline):

7

    print(token)

Python

1

TokenInfo(type=62 (ENCODING),  string='utf-8')

2

TokenInfo(type=1  (NAME),      string='color')

3

TokenInfo(type=54 (OP),        string='=')

4

TokenInfo(type=1  (NAME),      string='input')

5

TokenInfo(type=54 (OP),        string='(')

6

TokenInfo(type=3  (STRING),    string="'Enter your favourite color: '")

7

TokenInfo(type=54 (OP),        string=')')

8

TokenInfo(type=4  (NEWLINE),   string='')

9

TokenInfo(type=0  (ENDMARKER), string='')

(Note that for the sake of readability, I’ve omitted a few columns from the result above — metadata like starting index, ending index, a copy of the line on which a token occurs, etc.)

#code quality #code review #static analysis #static code analysis #code analysis #static analysis tools #code review tips #static code analyzer #static code analysis tool #static analyzer

4 Ways You Can Get Rid of Dirty Side Effects for Cleaner Code in JavaScript

According to an analysis, a developer creates 70 bugs per 1000 lines of code on average. As a result, he spends 75% of his time on debugging. So sad!

Bugs are born in many ways. Creating side effects is one of them.

Some people say side effects are evil, some say they’re not.

I’m in the first group. Side effects should be considered evil. And we should aim for side effects free code.

Here are 4ways you can use to achieve the goal.

1. use strict;

Just add use strict; to the beginning of your files. This special string will turn your code validation on and prevent you from using variables without declaring them first.

#functional-programming #javascript-tips #clean-code #coding #javascript-development #javascript

Making List-Like Objects in Python - The Right Way

In this post, we will be talking about how Python likes to deal with “list-like objects”. We will be diving into some quirks of Python that might seem a bit weird and, in the end, we will hopefully teach you how to build something that could actually be useful while avoiding common mistakes.

Part 1: Fake lists

Let’s start with this snippet.

class FakeList:
    def __getitem__(self, index):
        if index == 0:
            return "zero"
        elif index == 1:
            return "one"
        elif index == 2:
            return "two"
        elif index == 3:
            return "three"
        elif index == 4:
            return "four"
        elif index == 5:
            return "five"
        elif index == 6:
            return "six"
        else:
            raise IndexError(index)

f = FakeList()

A lot of people will be familiar with this:

f[3]
## <<< 'three'

__getitem__is the method you override if you want your instances to respond to the square bracket notation. Essentiallyf[3]is equivalent tof.__getitem__(3).

#python #list-like-objects #code #coding #lists #hackernoon-top-story #python-programming-lists #good-company