@magnet/common

Shared foundation for the Magnet packages.

This package has no runtime dependencies. It provides signal-related types and small runtime helpers used across the rest of the workspace.

Install

JSR

deno add jsr:@magnet/common

npm via JSR

npx jsr add @magnet/common

npm

npm install @magnet-js/common

Types

• AnySignal<T> — either a read-only or writable reactive signal.
• Compute — creates a reactive value derived from other signals.
• Computed<T> — reactive value that can be read synchronously.
• State<T> — reactive value that can be read and updated.
• Store — creates a reactive, writable value.
• SignalAPI — complete signal implementation to inject as a dependency: isSignal, effect, state, computed.
• IsSignal — determines whether an unknown value is a signal; implementations decide how the check is performed.
• SignalOptions<T> — customizes how a signal compares new values to previous ones.
• Effect / EffectCallback / Cleanup — reactive effect primitives.
• Maybe<T> — value that may be missing or void.
• MaybeSignal<T> — plain value or any reactive wrapper of that value.
• MaybeArray<T> — single value or a list of the same value.
• MaybeNestedArray<T> — plain value or a recursive array of the same value.
• MaybeNestedSignals<T> — plain value or a recursive array of reactive values.
• Dict<T> — plain object whose values all share the same type and keys are strings.
• CustomElementName — valid tag name for a custom HTML element.
• Falsy — re-exported from @std/assert.

Runtime helpers

browser()

Detects whether the current environment has a DOM.

import { browser } from "@magnet/common";

if (browser()) {
  // DOM-only code
}

createEmpty<T>()

Creates a dictionary object with no inherited properties.

import { createEmpty } from "@magnet/common";

const dict = createEmpty<Record<string, number>>();
dict.foo = 1;

isArray(value)

Checks whether a value is an array.

isFunction(value)

Checks whether a value is callable.

isString(value)

Checks whether a value is a string.

License

MIT © 2026 Fernando G. Vilar.