blank-object
Object.create(null) turns out to be quite slow to alloc in v8, but instead if
we inherit from an ancestory with proto = create(null)
we have nearly
the same functionallity but with dramatically faster alloc.
var BlankObject = ; var bo = ;
This is designed for a presence check map[key] !== undefined
since in
is also slow like hasOwnProperty
, delete
and Object.create
.
{} { thisstore = ; } { return thisstorekey !== undefined; } { let val = thisstorekey; return val === UNDEFINED ? undefined : val; } { thisstorekey = val === undefined ? UNDEFINED : val; }