The function whose reactive dependencies are tracked.
The callback function to execute when tracked dependencies change.
Optional updates: Map<string, UpdateDataRecord>Optional options: { The options for the reaction function.
The number of milliseconds to delay the execution of the callback function.
An optional name for the reaction.
An optional signal to abort the reaction.
An optional type for the reaction. Defaults to "reaction".
A function that can be called to unsubscribe the callback function from changes in the tracked dependencies.
const a = atom(0);
const b = atom(0);
let foo = 0;
// runs only data-function to get dependencies
// and then subscribes to changes in a and b
reaction(
() => [a.value, b.value],
() => {
foo++;
}
);
console.log(a.value, b.value, foo); // 0 0 0
a.value++;
console.log(a.value, b.value, foo); // 1 0 1
b.value++;
console.log(a.value, b.value, foo); // 1 1 2
batch(() => {
a.value++;
b.value++;
});
console.log(a.value, b.value, foo); // 2 2 3
Tracks reactive items used by the specified data function and subscribes the provided callback function to changes in these items. This ensures that the callback is executed whenever any of the tracked dependencies change, allowing for reactive updates based on the data function.