Angular front-end migration and performance overhaul

Context

A sales management application used by six hundred internal users, built on an Angular version five major releases out of date. Load times exceeded eight seconds on search screens, and the end-to-end test suite failed randomly.

Problem

Framework security updates could no longer be applied, the front-end team avoided touching the most complex search screens, and every release was accompanied by manual acceptance testing across sixty journeys.

Objectives

• Migrate the application to a supported Angular version
• Bring search screens under two seconds of perceived load time
• Make the end-to-end test suite reliable and usable

Role

Lead front-end developer and technical referent, pairing with two internal developers to ensure continuity after the engagement.

Solution

The migration was prepared with an inventory of screens and their dependencies, then split into eleven shippable batches. Each batch went to production after its related journeys were verified, which avoided a migration branch maintained for months. Search screens were reworked in depth: server-side pagination, reference data caching, removal of unreleased subscriptions and progressive replacement of duplicated state with signals. Perceived load time dropped from over eight seconds to under two seconds on the heaviest screens. The end-to-end suite was rebuilt around sixty critical journeys with explicit selectors and isolated test data. It now runs on every release and its random failure rate has fallen to a workable level.

Architecture

An Angular application built from standalone components, organised by functional domain with one data service per domain. Global state is limited to shared filters and the user session; everything else relies on component-local signals. The API client is generated from the Spring Boot OpenAPI specification, removing contract drift. End-to-end tests run in containers, with a simulated back end for error cases and a full environment for acceptance journeys.

Results (samples)

• Application migrated to a supported Angular version
• Search screens brought under two seconds of perceived load time
• Reliable end-to-end test suite running on every release
• Two internal developers autonomous on the new conventions

Indicators (samples)

• Perceived load time on search screens

  8.4 s to 1.8 s

  Simulated measurements in a demonstration environment — demonstration sample

• Migration batches shipped continuously

  11

  Illustrative breakdown — demonstration sample

• Journeys covered by end-to-end tests

  60

  Indicative volume — demonstration sample

Technologies

• TypeScript
• Spring Boot
• Angular
• RxJS
• NgRx
• Docker
• Playwright

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