Mockup of an observable with multiple entries

multiobservable.jl

mutable struct Multiobservable
    value::NamedTuple
    listeners::Vector
end

Multiobservable(nt) = Multiobservable(nt, [])

function Makie.Observables.on(f, m::Multiobservable, syms::Symbol...)
    push!(m.listeners, f)
    f
end

function trigger!(m::Multiobservable, syms::Set{Symbol})
    for l in m.listeners
        l(m.value, syms)
    end
end

function Base.push!(m::Multiobservable; kwargs...)
    m.value = typeof(m.value)(map(keys(m.value), m.value) do key, value
        get(kwargs, key, value)
    end)
    trigger!(m, Set{Symbol}(keys(kwargs)))
end

m = Multiobservable((a = 1, b = 'b', c = 3.0))

on(m) do nt, syms
    println("Update received")
    for sym in syms
        println(" - ", sym, " was updated to ", nt[sym])
    end
end

push!(m, a = 2, b = 'c')