`InfiniteScroll`¶

Append the next fragment when a pagination sentinel is revealed.


Import	`from hedron import InfiniteScroll`
Distribution	`hedron`
Backend activity	When revealed
Normal render mode	`RenderMode.FRAGMENT`

Live demo¶

DemoCode

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

Deployment completed
Review approved

Docs sim: click Load more (real apps use hx-trigger=revealed; auto-reveal is not simulated).

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

app.py

import os

from hedron import ComponentRef, Fragment, Hedron, InfiniteScroll, Page, Stack, html, swap

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

feed = app.region("event-feed")
ref = ComponentRef(
    logical_id="events",
    path="/events",
    target=feed.selector,
    swap="beforeend",
)


@app.page("/")
def home() -> Page:
    return Page(
        Stack(
            html.ol(
                html.li("Deployment completed"),
                html.li("Review approved"),
                id=feed.id,
            ),
            InfiniteScroll(ref=ref, target=feed.selector, swap="beforeend"),
        ),
        title="InfiniteScroll",
    )


@app.view("/events", fragment_regions=(feed,))
def more():
    return swap(Fragment(html.li("Tests passed"), html.li("Release published")))

Basic use¶

from hedron import ComponentRef, InfiniteScroll
component = InfiniteScroll(ref=ComponentRef('next-events', '/events', params={'page': 2}), target='#event-list')

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

How it works¶

The sentinel uses HTMX's revealed trigger and appends to the selected collection. The response should contain new records plus the next sentinel, or omit the sentinel when no pages remain.

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¶

InfiniteScroll(*, ref, target, swap='beforeend')

Parameter	Type	Meaning
`ref`	`ComponentRef`	Typed next-page endpoint.
`target`	`safe CSS selector`	Collection receiving appended nodes.
`swap`	`str`	Usually `beforeend`.

Composition and backend behavior¶

Keep InfiniteScroll 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¶

Provide a visible Load more fallback and announce how many items were added without moving focus.

Security¶

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

Common mistakes¶

Do not create an endless keyboard or screen-reader experience with no way to reach following page content.
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

InfiniteScroll¶