🔍 Streamlit Code Diff

A simple Streamlit component for code diff visualization using v-code-diff. Great for displaying code changes, git diffs, and side-by-side comparisons.

Features

• Automatic Theme Detection - Adapts to Streamlit's light/dark theme
• Multi-Language Support - Syntax highlighting for 10+ programming languages
• Customizable Display - Side-by-side or line-by-line diff formats
• Granular Diff Styles - Word-level or character-level difference highlighting

Installation

pip install streamlit-code-diff

Quick Start

import streamlit as st
from streamlit_code_diff import st_code_diff

old_code = """def hello():
    print("Hello")"""

new_code = """def hello(name="World"):
    print(f"Hello, {name}!")"""

# Display the diff
result = st_code_diff(
    old_string=old_code,
    new_string=new_code,
    language="python"
)

st.write(f"Changes detected: {result['isChanged']}")

Parameters Reference

st_code_diff()

Display a code diff visualization.

Parameters

Parameter	Type	Default	Description
old_string	str	Required	Original code content
new_string	str	Required	Modified code content
language	str	"plaintext"	Programming language for syntax highlighting
output_format	"line-by-line" | "side-by-side"	"side-by-side"	Display format
diff_style	"word" | "char"	"word"	Granularity of diff highlighting
context	int	5	Number of context lines around changes
filename	str | None	None	Original filename to display
new_filename	str | None	None	New filename to display
theme	"light" | "dark" | None	None	Force theme (auto-detects if None)
trim	bool	True	Remove leading/trailing whitespace
no_diff_line_feed	bool	True	Ignore line ending differences
height	str | None	None	Maximum height (e.g., "300px", "50vh")
force_inline_comparison	bool	False	Force inline comparison (word/char level)
hide_header	bool	False	Hide header bar
hide_stat	bool	False	Hide statistical part in header bar
ignore_matching_lines	str | None	None	Pattern to ignore matching lines (regex)
key	str | None	None	Unique component key

Returns

Returns a dictionary with diff statistics:

{
    "isChanged": bool,    # Whether differences were detected
    "addNum": int,        # Number of added lines
    "delNum": int         # Number of deleted lines
}

Supported Languages

The component supports syntax highlighting for:

• plaintext (default)
• python
• javascript / js
• typescript / ts
• json
• yaml / yml
• java
• bash / shell
• sql
• html
• xml
• css
• markdown / md

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• v-code-diff - The core diff visualization library
• Streamlit - The amazing framework that makes this possible
• highlight.js - Syntax highlighting support