watch should type old value as possibly undefined #253
Description
Docs: https://vue-composition-api-rfc.netlify.com/api.html#watch (Watching Multiple Sources)
Test:
setup() {
const test = ref({a: 0, b: 0}); //reactive({a: 0, b: 0});
watch(
() => [test.a, test.b],
([newA, newB], [oldA, oldB]) => console.log(newA, oldA, newB, oldB)
);
}
Result
Test:
setup() {
const test = reactive({a: 0, b: 0});
watch(
() => [test.a, test.b],
(newValues, oldValues) => console.log(newValues, oldValues)
);
}
Result:
Array[0, 0], undefined