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reactivity
also signals, Vue reactivity
A signal updates the computations that read it. Assigning state in React does not do that mid-render.
What is reactivity?
Reactivity tracks which computations read a value and reruns them when it changes. Vue, Solid, and MobX work this way. React state is different: setting state schedules a render, and a closure already running keeps the old value. Replacing an object can drop the proxy if you mutate a plain copy. A store written during render retriggers itself.
Why does reactivity matter when vibe coding?
The draft treats a signal like useState, or useState like a signal. It mutates a reactive object inside render, or it reads a signal once into a local and never sees updates.
How do you do reactivity?
Read the signal in the computation that should update. Do not mutate the store during render. Do not copy a reactive object into a plain one and expect subscribers. In React, set state and render again.
How do you ask a model for reactivity?
Use the reactivity model of (Vue, Solid, or React) for (state). Do not mix signals and useState. Do not mutate the store during render. Computations that display the value must read it directly.
What goes wrong with reactivity?
Destructuring a reactive object, which copies the current fields and leaves the binding behind.