`Fragment`¶

Return several sibling nodes without adding a wrapper element.


Import	`from hedron import Fragment`
Distribution	`hedron`
Backend activity	Common for HTMX
Normal render mode	`RenderMode.FRAGMENT`

Live demo¶

DemoCode

Docs simulation — not a running Hedron server. Interactive demos show a “Simulated HTMX” trace when applicable.

DraftProfileClick refresh to inject sibling nodes.

Minimal runnable app.py that reproduces this demo (real Hedron, not the docs simulator):

app.py

import os

from hedron import Fragment, Hedron, Page, RefreshButton, Stack, html, swap

app = Hedron(
    title="Fragment demo",
    security="standard",
    explorer="off",
    session_secret=os.environ.get("HEDRON_SESSION_SECRET", "dev-only"),
)

target = app.region("fragment-demo-target")


@app.page("/")
def home() -> Page:
    return Page(
        Stack(
            html.div(
                html.span("Draft"),
                html.span(html.strong("Profile"), html.small("Click refresh to inject siblings.")),
                id=target.id,
            ),
            RefreshButton.for_region(
                target,
                href="/profile-fragment",
                label="Refresh fragment",
                swap="innerHTML",
            ),
        ),
        title="Fragment",
    )


@app.view("/profile-fragment", fragment_regions=(target,))
def refresh():
    return swap(
        Fragment(
            html.span("Saved"),
            html.span(
                html.strong("Profile updated"),
                html.small("Two siblings returned as a Fragment."),
            ),
        )
    )

Basic use¶

from hedron import Alert, Fragment, Text
component = Fragment(Alert('Saved', tone='success'), Text('The record is current.'))

Compose under Page for full documents, or return from a fragment route for HTMX swaps.

How it works¶

A fragment flattens its children into the render stream. It is ideal for targeted HTMX responses because it does not change the target's surrounding layout or introduce an accidental DOM node.

This component can initiate or represent a backend interaction. The live documentation intercepts that interaction with JavaScript and shows the same pending, success, or replacement states without making a real request. In an application, keep the URL, authorization, validation, and returned fragment on the server; JavaScript is only progressive enhancement.

Constructor and parameters¶

Fragment(*nodes, children=None)

Parameter	Type	Meaning
`nodes`	`NodeLike`	Positional renderable sibling nodes.
`children`	`NodeLike \| sequence \| None`	Keyword alternative; combines with positional nodes.

Composition and backend behavior¶

Keep Fragment at the smallest semantic boundary. Fragment routes should return only the replaced region and preserve stable target IDs across success, validation, empty, loading, and error responses.

Mutating flows must use POST, validate CSRF, authorize on the server, re-validate typed input, and return a bounded fragment. GET remains safe and repeatable; native submit should still work without HTMX.

Accessibility¶

After a swap, focus and live-region behavior still belong to the response content; a wrapper-free result does not announce itself.

Security¶

Escaping and SafeUrl / TrustedHtml are framework concerns; authorization and data exposure remain application code. Redact secrets before rendering.

Common mistakes¶

Do not rely on a fragment to carry an id, class, or HTMX target—there is no wrapper on which to place attributes.
Do not copy docs-preview JavaScript into an application server.

Testing¶

from hedron import RenderMode, render

result = render(component, mode=RenderMode.FRAGMENT)
assert result.html
assert not result.diagnostics

All component demos · Built-in API · Testing

Fragment¶