The Rise of Signals – Solid, Qwik, and React’s New RFC

Note: This article was originally published on April 1, 2024. Some information may be outdated.

Signals are becoming one of the most discussed ideas in front-end frameworks lately.

They offer a lightweight, fine-grained reactivity model. Unlike traditional state systems like useState in React, signals let you track and react to changes at a lower cost.

What Are Signals?

A signal is a reactive value. You create it once, and when it changes, everything that uses it updates automatically.

In SolidJS:

import { createSignal } from "solid-js"

const [count, setCount] = createSignal(0)

// Reactive usage
<p>Count: {count()}</p>
<button onClick={() => setCount(count() + 1)}>Increment</button>

This is different from React’s model, which needs rerendering the whole component to update the UI.

Why Use Signals?

• Fine-grained updates (only parts that need to change will change)
• Better performance for large or reactive UIs
• More declarative and less boilerplate

Qwik and Resumability

Qwik also uses signals at its core, but it adds resumability on top. That means it doesn’t hydrate the whole app--only the parts the user interacts with.

import { component$, useSignal } from "@builder.io/qwik"

export const Counter = component$(() => {
  const count = useSignal(0)

  return (
    <button onClick$={() => count.value++}>
      Count: {count.value}
    </button>
  )
})

This makes Qwik fast even on large apps, as only interactive components are hydrated.

React’s Signals RFC?

React’s core team is also considering a signals-like pattern. While it's still early, the discussion shows interest in moving toward more efficient reactivity in the long run.

Developer Satisfaction

Frameworks like Solid and Qwik consistently report very high satisfaction in developer surveys. Once developers try signals, they often don’t want to go back.

Final Thoughts

Signals aren’t just a trend. They represent a shift toward more efficient, scalable UI logic. Whether you’re using Solid, Qwik, or waiting for React’s version, it’s worth learning this pattern now.

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Originally published at letanure.dev