QUESTION: Why is obj.__proto__=... being used instead of calling Object.create

[g00dnatur3]

In the ./lib/express.js & in the ./lib/router/index.js (and probably more places) the __proto__ is being set directly either in the form obj.__proto__ = ... or in the form obj = { __proto__: ... }

Mozilla does not recommend this:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/proto

they say it will heavily impact performance in modern javascript engines... I am not sure how relevant this is to vp8 engine, but Mozilla suggests using Object.create instead.

Is there a reason why you opted no to use Object.create?

Just very curious about this decision.

Thank you

[rlidwka]

Because obj is not an object but a function. You can't possibly use Object.create there.

Also, see discussion in #2413

[dougwilson]

__proto__ is now part of the ES6 standard. There are several other questions/discussions in this repo. Feel free to search around in here to see them. #1967 was the first I searched up for you :)

[aoberoi]

Sorry for reviving an old issue, but I'm running node v4.2.2 and Object.setPrototypeOf() is available. I'm not sure which version it was added in, but it seems (at least the 4.x versions of) express targets 0.10.x as a minimum. Do we have any word on what version of node express v5 will target?

[dougwilson]

There is currently an open discussion about this (you can find it by looking at the open issues), but the highest minimum we will go for 5.0 is 4.0.0. Regardless, the property is part of the ES6 spec and will likely stick around for some time. Everyone asking so far has not had any legitimate reason not to use it besides "oh, it's deprecated". That's all well and good, but as long as we support node.js versions without setPrototypeOf, we have no other choice.