Invoice Generation Web App
Tags: javascript, invoice, webapp, code
Published: 2023-05-17 04:17:58


**_Are you looking for a quick and efficient way to generate and print invoices for your business? Look no further! _**

In this blog post, I'll walk through the JavaScript code implementation of an invoice generation web app that I built and explain how each part works. By the end, you'll have a better understanding of the code and be able to customize it to fit your specific needs.


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/cj099oujrbxkjx3ybl1r.png)

**Introduction**
The JavaScript code provided implements the functionality of an invoice generation web app. It allows users to input item details, such as item name, currency, amount, and quantity, and dynamically renders them on the page. The app calculates the total cost of each item and displays the overall total. It also provides the option to remove items and includes a form for users to enter their details.

Let's dive into the code and break it down section by section.

**Importing Dependencies**
The code starts by importing necessary dependencies using ES6 modules. The textSection and renderUserDetails functions are imported from the "user-form.js" file, and the popupRender function is imported from the "popup.js" file. These functions are used later in the code to render the user details and display popups, respectively.

**Adding a Print Button**
The next part of the code adds a print button to the HTML page and attaches an event listener to it. When the button is clicked, the printPage function is called, which handles the printing functionality. This function hides certain elements on the page, removes the "remove-item" buttons, and triggers the window.print() method to open the print dialog box.

**Rendering the User Interface**
After setting up the print functionality, the code proceeds to render the initial user interface. The textSection content is added to the "form-area" element using innerHTML.

**Handling Input and Output**
The code sets up event listeners and functions to handle user input and output. When the "addInputsBtn" button is clicked, an event listener function collects the input values and creates a new object using the itemConstructor constructor function. This object is then added to the items array.

The code calculates the total unit costs and renders the input values dynamically in the "itemOutput" element. Each item is wrapped in an HTML template, allowing easy removal when the user clicks the "remove" button. The event listener function for removing items filters out the selected item from the items array and updates the rendered HTML accordingly.

**Generating Random IDs**
The code includes a generateRandomID function that generates a random ID for each item object. It uses a loop to select random characters from a predefined set and concatenates them to form a unique ID. This function ensures that each item has a distinct identifier.

**Handling Form Submission**
Next, an event listener is added to handle form submission. When the "submit-form-button" is clicked, the listener function checks if the form is valid. If it is, the function displays the user details section, calls the renderUserDetails function to render the details, hides the form, and saves the user form inputs to local storage. If the form is not valid, an alert is shown to prompt the user to fill out all required fields.


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/vduuzcj1v1458qh38z6r.png)

**Conclusion**
Congratulations! You've now reviewed and understood the JavaScript code I built that powers the invoice generation web app. You learned about adding a print button, handling user input and output, generating random IDs, and handling form submission.

Feel free to use the app! Whether you're running a small business or need a personal invoice generation tool, this code provides a solid foundation for your project.

Live site: https://invoice-creator-web-app.netlify.app/


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/qjfvz9abfwcshilx8qfv.png)

Please feel free to follow me on LinkedIn: https://www.linkedin.com/in/jamespalderman/