All writing

Angular · Architecture

Migrating a Large Angular App from Material to PrimeNG

How to migrate a multi-module Angular workspace one screen at a time, while feature development keeps shipping around you.

Jaymin Maheta 9 min read
Share:
Component library code on a screen

Why migrate at all

Angular Material is a solid baseline, but on data-dense enterprise products it runs out fast. Teams end up wrapping tables, overlays and form controls in custom code to get filtering, virtual scrolling, dense layouts and rich theming — until the "wrapper layer" is bigger than Material itself.

PrimeNG ships more of that out of the box: a real theming system, a wider component set for enterprise UI (data tables, trees, timelines, complex form controls), and fewer places where you're fighting the library instead of building the product. The migration is worth it when the wrapper code is costing you more than the switch would.

The screen-by-screen strategy

Run both libraries side by side

Install PrimeNG alongside Material rather than ripping Material out first. Namespace the CSS resets so the two design systems don't leak into each other's components.

Migrate by feature module

Pick module boundaries as migration boundaries. A module is either fully Material or fully PrimeNG at any point — never mixed within the same screen.

Start with the highest-friction screens

Migrate the screens where Material's limitations are actively costing engineering time first — usually dense tables and multi-step forms — to get the biggest win early.

Build shared components once

Wrap PrimeNG's primitives in your own thin component layer from day one, so a second library swap — or a design change — only touches one place.

Keep a visual regression net

Screenshot the module before and after migration. Enterprise UIs have too many edge-case states — empty, loading, error, dense — to trust a manual pass alone.

Delete Material only at the end

Don't remove the Material package until the last module is migrated. Keeping both installed briefly costs bundle size, not correctness — a fine trade during transition.

Where it actually gets hard

The component swap is the easy part. The hard part is everything Material was doing for you implicitly — overlay z-index stacking, focus trapping in dialogs, form control value accessors, and theme tokens referenced from a dozen unrelated stylesheets.

Overlays are the most common failure: PrimeNG dropdowns and date pickers can render behind Material dialogs that are still mid-migration. Fix the layering once, centrally, in the theme configuration — not per component as issues surface.

Custom `ControlValueAccessor` implementations also need re-testing against PrimeNG's form components, since default value formats and change-detection timing aren't always identical to Material's.

The takeaway

A Material-to-PrimeNG migration doesn't need a rewrite or a feature freeze. Treat module boundaries as migration boundaries, wrap the new library in your own components immediately, and fix cross-cutting issues like overlay stacking centrally rather than screen by screen. The product keeps shipping the whole time.

Let's talk about your frontend