In javascript you can do the following
const obj1 = {a:1, b:'blue', c:true};
const obj2 = {...obj1, d:3, e:'something else'};
and you object 2 will have all of obj 1 in it.
Is there a way to do this in lua?
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1 Answer
You'd have to write your own function for this purpose:
local function add_missing(dst, src)
for k, v in pairs(src) do
if dst[k] == nil then
dst[k] = v
end
end
return dst -- for convenience (chaining)
end
which you may then use as follows:
local obj1 <const> = {a = 1, b = 'blue', c = true}
local obj2 <const> = add_missing({d = 3, e = 'something else'}, {a = 1, b = 'blue', c = true})
Note: JavaScript's spread operator also guarantees a certain order of execution; that is, in your example fields from obj2 would override those from obj1, which is why I've included an explicit nil check to only include missing fields:
> {...{a: 2}, a: 1}
{ a: 1 }
> {a: 1, ...{a: 2}}
{ a: 2 }
