Object.ts  

Reactive utilities and object helpers for JavaScript

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Object.ts is a lightweight library providing reactive primitives and object utilities for JavaScript. It is a minor sibling of Uniform.TS, originally created in early 2024 and partially revisited in 2025. The library is primarily used in internal projects and is designed to be compatible with modern reactive libraries.

Table of Contents

• Features
• Installation
• Usage
• API Reference
  • Reactivity
  • DOM Utilities
• Related Projects
• License

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Features

• Non-intrusive subscriptions: Subscribers do not retain references to target objects.
• Efficient reactivity: Triggers only on actual value changes.
• Compatibility: Works with recent versions of popular reactive libraries.

Installation

npm install object.ts

or

yarn add object.ts

Usage

import { makeReactive, ref, subscribe } from 'object.ts';

const state = makeReactive({ count: 0 });

const unsubscribe = subscribe(state, () => {
  console.log('State changed:', state.count);
});

state.count = 1; // Triggers subscriber
unsubscribe();   // Unsubscribe when needed

API Reference

Reactivity

• makeReactive(initial) Creates a reactive primitive from an existing object.

• subscribe(obj, [key], callback) Subscribes to changes in an observable object, Set, or Map.

  • Supports [obj, key] to subscribe to a specific property.
  • Returns an unsubscribe function.

• deref(obj) Dereferences a WeakRef or .value-based object.

• promised(obj) Wraps an awaitable promise as a reactive value.

  • Reacts only to Promise.resolve.

• ref(initial) Creates an observable reference with a value property.

• computed(sub) Similar to ref, but computes its value from a reactive source.

  • Setting the value has no effect on the source.

• unified(...objs) Combines multiple observable objects into one (read-only).

• remap(obj, cb) Creates a remapped reactive object with a different keyset (read-only).

• weak(initial) Like ref, but the value is always a WeakRef and may disappear without notification.

• conditional(cond, ifTrue, ifFalse) Reactive value that switches between ifTrue and ifFalse based on cond.value.

• safe(target) Prepares an object for serialization to JSON or JSOX.

DOM Utilities

• matchMediaRef(mediaValue) Creates a reactive ref based on a matchMedia query.

• localStorageRef(name, initial) Creates a persistent reactive ref synchronized with localStorage.

  • Note: Does not currently react to changes from other tabs or windows with the same key.

Related Projects

• BLU.E (2025) — Built on top of Object.ts.
• Uniform.TS — The major sibling project.

License

This project is licensed under the MIT License.

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For more information, see the GitHub repository.