Does JavaScript creates object literal with Object constructor under the hood?

Question

when we do let obj = {}; and console.log(obj.__proto__) it prints an object with constructor so does that mean object literal is being created by Object constructor under the hood

No. But both {} and the new Object constructor use the same internal mechanism under their hoods. — Bergi
– Bergi, Commented Aug 19, 2021 at 20:12
"it prints an object with constructor" - all that means is that objects created from literal inherit from Object.prototype. It doesn't mean any constructor was invoked. You can achieve the same yourself with Object.create(Object.prototype). — Bergi
– Bergi, Commented Aug 19, 2021 at 20:19

Tom · Accepted Answer · 2022-02-17 06:12:04Z

1

As @Bergi says, both forms use the same internal mechanism under the hood.

First, an object literal inside a JS script is not JSON, it is an "object initializer":

// object initializer, NOT JSON
let myPet = {
    species: 'Dog',
    ageMs: 1000 * 60 * 60 * 24 * 365.24 * 5 // ~5 years, in millis
}

While no constructor is explicitly invoked by the literal notation, it's also not the case that the created object is just the literal properties; the JS engine still does some setup work. I've never dug into this before, but it appears that the spec calls that setup work "OrdinaryObjectCreate".

answered Feb 17, 2022 at 6:12

Tom

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