Common Angular Change Detection Mistakes That Slow Down Large Applications

Angular's change detection is not inherently slow, but performance problems arise when applications accumulate unnecessary work during rendering cycles. A frequent culprit is calling methods directly from templates, which Angular re-executes on every check since it cannot determine whether the output has changed. As applications grow, these template methods often expand to include formatting, filtering, and permission logic, significantly increasing rendering cost. Developers are advised to pre-compute and attach transformed data to objects before they reach the template, keeping templates focused purely on display. While ChangeDetectionStrategy.OnPush reduces how often checks occur, it does not eliminate inefficient rendering logic, so it should be treated as one part of a broader performance strategy rather than a standalone fix.