Function computed

Creates a new computed signal.

The compute callback will be executed (and re-executed as necessary) to provide the current value. The function body of compute is tracked automatically: any reactive values used by compute will be watched automatically; if any of them changes then the computed value will be updated as well.

NOTE: the compute callback should not have any side effects as it may be called any number of times if its dependencies change.

Example:

const foo = reactive(1);
const doubleFoo = computed(() => foo.value * 2);
console.log(doubleFoo.value); // 2

foo.value = 2;
console.log(doubleFoo.value); // 4
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