At first glance, building a scheduling or timeline-based UI sounds straightforward.
You have:
- a time axis
- some events
- maybe a grid
How hard can it be?
If you’ve ever actually built one in React Native, you probably know the answer already:
it gets complicated very quickly.
When scheduling stops being “just a calendar”
Most scheduling UIs start simple:
- a daily planner
- a basic calendar
- a list of time-based items
But real-world requirements show up fast:
- hundreds of items on screen
- thousands of time-based events
- overlapping ranges
- multi-day views
- smooth scrolling on mobile
- gestures (drag, resize, long press)
- TV or tablet support
At that point, you’re no longer building a “calendar”.
You’re building a time-based rendering engine.
The biggest pain points (from real projects)
1. Performance with large datasets
Rendering a few events is easy.
Rendering hundreds of rows and thousands of events — not so much.
You start fighting:
- dropped frames
- memory usage
- layout thrashing
- scroll jank
Even with virtualization, timelines are harder than lists because:
- positions depend on time calculations
- items overlap
- everything needs to stay aligned to a grid
2. Layout math everywhere
Schedulers are basically math-heavy UIs:
- converting timestamps to pixel positions
- handling overlaps
- snapping to time intervals
- recalculating layouts on resize or orientation change
Once you support multiple views (day, multi-day, timeline),
layout logic tends to spread across the entire codebase.
3. Gestures vs. smooth UX
On mobile, gestures are expected:
- drag & drop
- resizing
- scrolling
But combining:
- gestures
- animations
- large datasets
often leads to trade-offs:
- smooth scrolling vs. interactive gestures
- responsiveness vs. correctness
It’s very easy to end up with a UI that works, but feels fragile.
4. Mobile and TV are different beasts
A lot of scheduling libraries focus on desktop web.
On mobile and TV:
- screen real estate is limited
- input methods differ (touch, remote control)
- performance budgets are tighter
TV especially introduces new challenges:
- focus-based navigation
- predictable movement
- no free-form gestures
Most teams underestimate this until late in the project.
Why many teams end up rebuilding everything
I’ve seen the same pattern over and over:
- Start with a simple custom implementation
- Add features one by one
- Performance starts degrading
- More edge cases appear
- The scheduler becomes the hardest part of the app
At some point, the scheduler:
- takes more time than core product features
- becomes risky to modify
- is painful to maintain
Yet it’s often mission-critical.
What I learned building a scheduling component
While working on scheduling and timeline-heavy UIs, a few things became clear:
- Scheduling UIs are infrastructure, not features
- Performance must be designed from day one
- Layout and rendering logic needs strong boundaries
- Mobile and TV need first-class consideration
Most importantly:
Schedulers shouldn’t be rebuilt from scratch for every project.
Opening the discussion
I’m curious how others approach this in React Native:
- Have you built a scheduler or timeline UI before?
- What was the hardest part — performance, layout, gestures, scale?
- Did you see issues only after data size increased?
- Did you build everything yourself or rely on a library?
I’d love to hear real-world experiences and lessons learned 👇
If you’ve fought with scheduling UIs before, you’re definitely not alone.
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