Develop An App in JavaScript That Can Download Any File From URL | HTML CSS and JavaScript

Introduction
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Meet Owner
Hi, I’m Malik Faizan, the founder of MalikCodex. As a passionate developer with years of experience, I have worked with a multitude of programming languages and technologies

About Any File Downloading App From URL in JavaScript (Videos, Images)
In this blog post, We will discuss how can we develop a custom file downloader app from URL in javascript. We will understand everything easily and also put a strong overview of the logic we used. So let's Get Started Now.

URL Validation In JavaScript Using Regex
Regex is all about matching characters or searching for a specific character or string using mathematical representation. In JavaScript, we can use the test function to validate any pattern in our case we have to search for something like this in the URL (/.(jpe?g|png|mp4)/) [Pattern Used]

Test Function in JavaScript
JavaScript test function helps us to validate URLs because in our case first, we have to check that either user is putting the correct URL that contains a valid file (Image or Video)

This is the complete logic behind URL validation let's move on to the next block where we discuss some functions we used to handle error and success messages with BTN disabling or enabling at the time of processing
Default Functions to handle Alert messages and button behavior
So after clearing the upper block we discuss how can we handle alert messages and BTN handling using functions we will create an error function, success function, Button disabled function, and reset function.

when we get any error we will use the error function to print an error message in red color and the success function when everything is ok if everything is ok we will use the resetUI function that enables the button and in the case of processing we disable the button. These are the functions we use to handle our next logic

Now let's move on to the final block where we discuss a request that we make to get the content of the file from the URL. For this last implementation, we call the last function downloadFile()

This function will use fetch req to get content from the URL and to handle the request properly we will use the try & catch statement in javascript to properly handle if the program fails and returns an error. Let's move on to the last block of this post.

Try and Catch Statement with Fetch API Request
We handle our last condition by using try-and-catch statements with fetch API requests. in a try block, we will use a fetch request, and if the program returns then we use the statement to return the blob and again the statement to return content or data.

Steps to Follow
1. Writing HTML Part
2. CSS For Beautiful Design
3. Integrate JavaScript
4. First Create All Default Functions
5. Get All Selectors
6. Create Error & Success Messages
7. Use onkeyup() JavaScript event listener to get value from input[type="URL"]
8. Use Regex to validate valid extensions from URLs such as [jpg, jpeg, png, mp4] // ... you can add more
9 Pattern Used [ /.(jpe?g , mp4 , png)/ ]
10. Add Click Button Event Listener to Download Button
11. Use the Try and Catch Condition to handle fetch API Request
12. that's it

Final Conclusion
By understanding the complete logic we will get our custom File Downloading App in JavaScript that can download Any File From the URL. You can explore more projects on my website and download the complete source code.

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