Print ticket in thermal printer directly from browser

In this post I will show you how to print a receipt in a thermal printer directly from web browser, without user interaction and confirm dialogs, by using a free plugin.

Step 1: download the plugin

You have to download the plugin, it’s for free, just go to the docs. If it asks you for firewall permission allow it, it is not a malicious file.

Step 2: the javascript library

In your project, include the JavaScript library called Impresora.js. You can download it from the GitHub repo, or from the docs.

When you include the library, the classes OperacionTicket and Impresora will be available.

Step 3: set up default printer

Here you can use the setImpresora method (call it with a printer obtained from getImpresoras), or go to the examples and use the buttons.

Step 4: hello, thermal printer

Now you can create a new Impresora instance:

let impresora = new Impresora();

The class constructor accepts a distinct URL if you want to provide an IP or if I change the port in the future, you are not forced to indicate the URL, by defualt it is localhost:8080

Once you have the instance, you can, for example, call the write method and finally the end method.

When the promise is resolved you should get a ticket printed in your thermal printer, if not, check the docs again and make sure you followed all the steps.

Remember: you can check all the examples source code.

Example: plugin capabilities

We will get a ticket like this, where we can set the font, alignment and some other things:

The code is as follows:

Once we have an Impresora instance we can call write, setFont, feed, cut, cutPartial, setFontSize and finally end.

Now you can use your thermal printer and create awesome receipts.