sindresorhus/on-change

Health v2 · maintenance only

Adoption not part of the score

2030 stars · 87 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

A tiny JavaScript library that watches objects and arrays for changes using the ES2015 Proxy API. It recursively detects deep mutations and invokes a callback with the change path, new value, previous value, and method data.

Use cases

• watch javascript object for changes
• detect deep property mutations in an object
• observe array changes like push or splice
• build reactive state without a framework
• track which object paths were modified
• unsubscribe from object change notifications

When to choose

• you need lightweight change detection for plain objects and arrays
• you want deep, recursive observation with change paths
• you're in a modern environment supporting ES2015 Proxy

When to avoid

• you need to support environments without Proxy (older browsers)
• you need a full reactive state management system with stores and subscriptions
• you need to observe non-object types or class instances with private fields

Facets

library · maturity stable

state-management developer-tools web-development frontend developer-tools browser proxy observer change-detection es2015-proxy npm-package nodejs javascript

Member repositories

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