previous Helper

template<size_t MaxDeps = 8, typename Source>
auto RxESP32::Helpers::Analysis::previous(Source &source, const typename Computed<decltype(source.get()), 1, MaxDeps>::Options &options = {})

Get previous value of signal.

Creates a Computed that returns the previous value (value before last change).

Since

v0.1.0

Signal<int> counter(0);
auto prev_counter = previous(counter);
// Initial: prev_counter.get() == 0
counter.set(1);  // prev_counter.get() == 0
counter.set(2);  // prev_counter.get() == 1
counter.set(3);  // prev_counter.get() == 2

Note

Stateful helper. On first call, returns initial value.

Template Parameters:
size_t MaxDeps = 8

Maximum number of dependents for the computed signal.

Parameters:
Source &source

Source (determines result type).

const typename Computed<decltype(source.get()), 1, MaxDeps>::Options &options = {}

Optional Computed configuration.

Returns:

Computed with previous values.

See Also