Summary
When rendering native HTML elements, PyJSX indents all child content for pretty-printed output. For elements where text content is semantically significant (especially <textarea>), this mutates the actual value.
Multiline strings passed as children are indented line-by-line, which breaks use cases like rich-text editors, form fields, or any textarea whose value must round-trip unchanged.
Environment
python-jsx / PyJSX: 0.4.0- Python: 3.12
Steps to reproduce
# coding: jsx
import pyjsx.auto_setup
from pyjsx import jsx
def TextareaField(value: str):
return <textarea name="body">{value}</textarea>
html = str(TextareaField("line1\n\nline2"))
print(repr(html))Actual output
<textarea name="body">
line1
line2
</textarea>Expected output
The textarea text content should be exactly line1\n\nline2, without added leading spaces.
Impact
We use PyJSX for an admin UI with a Markdown rich-text editor. Markdown loaded from the DB is rendered into a hidden textarea. PyJSX adds leading spaces to every line (worse in nested components). Markdown parsers then treat the content as a code block, the editor shows raw markdown, and saving persists corrupted content.
Likely also affects <pre>, <script>, <style>, and <title>.
Cause
pyjsx/jsx.py applies indent() to string children:
children_formatted = "\n".join(indent(str(child)) for child in children)
Suggested fix
Do not indent plain string children, at least for RCDATA/RAWTEXT elements like <textarea>. Alternatively, never indent str children and only pretty-print nested elements.
Summary
When rendering native HTML elements, PyJSX indents all child content for pretty-printed output. For elements where text content is semantically significant (especially
<textarea>), this mutates the actual value.Multiline strings passed as children are indented line-by-line, which breaks use cases like rich-text editors, form fields, or any textarea whose value must round-trip unchanged.
Environment
python-jsx/ PyJSX: 0.4.0Steps to reproduce
Actual output
Expected output
The textarea text content should be exactly
line1\n\nline2, without added leading spaces.Impact
We use PyJSX for an admin UI with a Markdown rich-text editor. Markdown loaded from the DB is rendered into a hidden textarea. PyJSX adds leading spaces to every line (worse in nested components). Markdown parsers then treat the content as a code block, the editor shows raw markdown, and saving persists corrupted content.
Likely also affects
<pre>,<script>,<style>, and<title>.Cause
pyjsx/jsx.pyappliesindent()to string children:Suggested fix
Do not indent plain string children, at least for RCDATA/RAWTEXT elements like
<textarea>. Alternatively, never indentstrchildren and only pretty-print nested elements.