ngx-signal-combinators

Composable boolean helpers built on Angular 20+ signals. The library exports tree-shakable utilities that let you combine Signal<boolean> values just like boolean expressions, while maintaining full type safety and reactivity.

Installation

npm install ngx-signal-combinators

The package is designed for Angular 20+ applications that leverage the standalone APIs.

Usage

API surface

Function	Description
and(...signals)	Returns a computed signal that is true when every source signal is currently true (empty input resolves to true).
or(...signals)	Returns a computed signal that is true when any source signal is currently true (empty input resolves to false).
not(signal)	Returns a computed signal that negates the current value of the supplied signal.
pr(signal, predicate)	Returns a computed signal that runs the predicate against the current value of the supplied signal.

Template example

Below are individual template snippets that demonstrate each helper (assuming the component exposes isSignedIn, hasPremium, isSuspended, searchTerm, and a predicate helper isNonEmpty as signals/functions):

and(...)

@if (and(isSignedIn, hasPremium)()) {
  <article class="premium-banner">
    Thanks for subscribing! Premium features unlocked.
  </article>
} @else {
  <article class="premium-banner--locked">Activate premium to unlock more features.</article>
}

not(...)

@if (not(isSuspended)()) {
  <aside class="account-status">Account in good standing.</aside>
} @else {
  <aside class="account-status--warning">Account currently suspended.</aside>
}

or(...)

@if (or(isSignedIn, hasPremium)()) {
  <section class="dashboard">Dashboard available.</section>
} @else {
  <section class="dashboard--locked">Sign in to access your dashboard.</section>
}

pr(...)

@if (pr(searchTerm, isNonEmpty)()) {
  <section class="search-results">
    Showing results for "{{ searchTerm() }}".
  </section>
} @else {
  <section class="search-results--empty">
    Enter a search term to see results.
  </section>
}

Testing

Unit tests are provided in tests/ngx-signal-combinators.spec.ts using Vitest. They verify every exported helper. Run them with:

npx vitest run

The tests assert that each computed signal reacts to updates emitted by the source signals. If you prefer a browser-like environment, enable the jsdom environment in your Vitest config.