node-terminal-simulator

Simulates the behavior of a terminal in NodeJS.

Motivation 💥

This small package provides a simple way to simulate the behavior of a terminal in NodeJS. The primary use case is to unit-test libraries or tools that interact with the terminal. It respects many special ANSI escape sequences, like cursor movement or deleting and inserting lines.

Features 🔥

✅ Simulates the behavior of a terminal in NodeJS.

✅ Supports ANSI escape sequences. (e.g. cursor movement, deleting and inserting lines)

✅ Easily assert the expected current displayed text in the terminal.

✅ Assert the color or style of any character visible in the simulated terminal.

✅ Send keys to the terminal to simulate user input.

✅ Accurately tracks the cursor position.

✅ Assert the lines that are pushed out of the visible terminal area.

✅ Easily extensible with custom escape sequences.

✅ Easily redirect stdout to the simulated terminal.

This project is by no means complete, but it's a good starting point. Feel free to open an issue or pull request if you have any suggestions for improvements like new escape sequences.

Limitations ⚠️

🔒 Escape sequences for colors (and other styles) are removed from the output. (You can still assert styles by using the getStylesAt(line, char) method on the Terminal instance.)

🔒 Some escape sequences are not recognized. (Feel free to contribute 😊)

Built With 🔧

• TypeScript

Usage Example 🚀

import { Terminal, DO_DELETE_LINE, DO_MOVE_LEFT_FULLY, DO_MOVE_UP } from 'node-terminal-simulator';

const t = new Terminal([100, 8]);

t.write('This is a test');
// Output:
// This is a test

t.write('. Additional new text.'); // Same line
// Output:
// This is a test. Additional text.

t.write('\n'); // New line
t.write('This is a new line.');
// Output:
// This is a test. Additional text.
// This is a new line.

t.write(DO_MOVE_UP); // \u001b[A
t.write(DO_MOVE_LEFT_FULLY); // \u001b[999D
t.write('This overwrites the first line.');
// Output:
// This overwrites the first line.text.
// This is a new line.

t.write(DO_DELETE_LINE); // \u001b[1L
// Output:
// This is a new line.

console.log(t.text);

assert(t.text === 'This is a new line.', 't.text should be "This is a new line."');

TODO: Add advanced usage examples.

Contributing 🧑🏻‍💻

Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are greatly appreciated.

If you have a suggestion that would make this better, please fork the repo and create a pull request. You can also simply open an issue with the tag "enhancement". Don't forget to give the project a star! Thanks again!

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

License 🔑

Distributed under the MIT License. See LICENSE.txt for more information.

Contact 📧

Janik Schumacher - @LoaderB0T - linkedin

Project Link: https://github.com/LoaderB0T/node-terminal-simulator