There was a time there where only few text editors available for programmers like Editplus, UltraEdit, etc.. they are all paid.
Then come Sublime, that become very popular among programmers, it was light weight, coded in python, allowed extending its features with plugins. Sublime is a paid text editor, but it allowed unlimited trail, that means you can keep using it for ever, only problem with it is, some times it keep showing a message when you save asking for you to purchase a license.
Recently Github created open source text editor called Atom. It was created in Node.js
Microsoft Visual Studio Code
Microsoft also released Open Source editor Microsoft Visual Studio Code
Adobe have come with Open Source Code editor called Adobe Brackets