how to add an variable when colliding?

[faytree]

i mean like when the circle for example collides a box,the box will add a variable.I know it's impossible but if you have an idea how to add an variable?

[Kilinich]

onCollide = (e) => {e.this._newVar := 0}

this will work too:
onCollide = (e) => {e.this._newVar = 0}

[faytree]

Thanks kilinich!