Core API Overview

The @signalis/core package provides the fundamental reactive primitives that power Signalis. These primitives are designed to be highly composable, performant, and easy to use.

Primitives

Signals

Writable reactive values that serve as the foundation of the reactivity system.

import { createSignal } from '@signalis/core';

const count = createSignal(0);
count.value = 5; // Update the value
console.log(count.value); // Read the value: 5

Derived

Readonly reactive computed values that automatically update when their dependencies change.

import { createSignal, createDerived } from '@signalis/core';

const count = createSignal(0);
const doubled = createDerived(() => count.value * 2);

console.log(doubled.value); // 0
count.value = 5;
console.log(doubled.value); // 10

Effects

Reactive side-effect functions that run automatically when their dependencies change.

import { createSignal, createEffect } from '@signalis/core';

const count = createSignal(0);
createEffect(() => {
  console.log(`Count is: ${count.value}`);
}); // Immediately logs: "Count is: 0"

count.value = 5; // Logs: "Count is: 5"

Resources

Async reactive values with built-in loading and error states.

import { createResource } from '@signalis/core';

const data = createResource(() => fetch('/api/data').then((res) => res.json()));

if (data.loading.value) {
  console.log('Loading...');
} else if (data.error.value) {
  console.log('Error:', data.error.value);
} else {
  console.log('Data:', data.value.value);
}

Stores

Proxy-based fine-grained reactive objects for managing nested state.

import { createStore, update } from '@signalis/core';

const store = createStore({
  count: 0,
  user: { name: 'Jane' },
});

// Read values directly (no .value needed!)
console.log(store.count); // 0

// Update using the update function
update(store, (draft) => {
  draft.count = 5;
  draft.user.name = 'Janet';
});

Utilities

Utility Functions

Helper functions for working with reactive primitives:

• batch() - Batch multiple signal updates
• isSignal() - Type guard for signals
• isDerived() - Type guard for derived values
• isReaction() - Type guard for reactions

Next Steps

• Explore each primitive in detail using the sidebar
• Check out examples to see them in action
• Learn about React integration