vide/docs/tut/crash-course/4-source.md

Sources

Sources are special objects that store a single value and are the core of Vide's reactivity.

A source can be created using source().

local source = vide.source

local count = source(0)

The value passed to source() is the initial value of the source.

The value of a source can be set by calling it with an argument, and can be read by calling it with no arguments.

count(count() + 1) -- increment count by 1

Sources can be derived by wrapping them in functions.

local count = source(0)

local text = function()
    return "count: " .. tostring(count())
end

print(text()) -- "count: 0"
count(1)
print(text()) -- "count: 1"

While the above can be achieved with plain variables, the use for sources will be obvious in the next part.