Change detection is core to Angular performance and responsiveness. Understanding how it works and how to optimize it makes a noticeable difference in how Angular apps behave under load.<\/p>\n\n\n\n
Angular’s change detection keeps component data in sync with the DOM. It sets up a change detector for each component, creating a tree structure that imitates the component hierarchy.<\/p>\n\n\n\n
When an event gets triggered, Angular runs change detection across the entire tree, from top to bottom. It checks each component for changes, and if it finds one, it updates only that part of the view accordingly.<\/p>\n\n\n\n
In large-scale apps, the default detection strategy can slow things down. That\u2019s where OnPush comes in. By using the OnPush change detection strategy, Angular only runs checks when:<\/p>\n\n\n\n
This reduces unnecessary updates and improves performance.<\/strong><\/p>\n\n\n\n Example<\/strong><\/p>\n\n\n\n In this setup, UserProfileComponent only updates its view when the user object reference changes, not when just one of its properties changes. This prevents Angular from running change detection unnecessarily.<\/p>\n\n\n\nts\nCopyEdit\nimport { Component, Input, ChangeDetectionStrategy } from '@angular\/core';\n \n@Component({\n selector: 'app-user-profile',\n template: `\n <h2>{{ user.name }}<\/h2>\n <p>{{ user.email }}<\/p>\n `,\n changeDetection: ChangeDetectionStrategy.OnPush\n})\nexport class UserProfileComponent {\n @Input() user: { name: string, email: string };\n}<\/code><\/pre>\n\n\n\nConclusion<\/h2>\n\n\n\n