The reason I ask is because I would expect js.Global.Get("console").Call("log", []byte{}) to get externalized as an empty Uint8Array:

Uint8Array {}

Not an empty Array.

Or is there a reason why numeric slices with 0 elements are treated differently than numeric slices with 1 or more elements?

Is this intentional by design, or an accidental oversight?

I'm guessing this was an accidental oversight, given that #597 (/cc @flimzy) looks like similar/identical issue, and it was resolved by #599.

Running the same code as above with latest GopherJS produces different results, that look more in line with what's expected:

$ goexec -quiet -compiler=gopherjs 'js.Global.Get("console").Call("log", (interface{})(nil))'
null

$ goexec -quiet -compiler=gopherjs 'js.Global.Get("console").Call("log", js.Undefined)'
undefined

$  goexec -quiet -compiler=gopherjs 'js.Global.Get("console").Call("log", []byte{1, 2, 3})'
Uint8Array [ 1, 2, 3 ]

$ goexec -quiet -compiler=gopherjs 'js.Global.Get("console").Call("log", []byte{})'
Uint8Array [  ]

$ goexec -quiet -compiler=gopherjs 'js.Global.Get("console").Call("log", ([]byte)(nil))'
Uint8Array [  ]

$ goexec -quiet -compiler=gopherjs 'js.Global.Get("console").Call("log", []string{"hi", "bye"})'
[ 'hi', 'bye' ]

$ goexec -quiet -compiler=gopherjs 'js.Global.Get("console").Call("log", []string{})'
[]

$ goexec -quiet -compiler=gopherjs 'js.Global.Get("console").Call("log", ([]string)(nil))'
[]

I'm guessing this was an accidental oversight, given that #597 (/cc @flimzy) looks like similar/identical issue, and it was resolved by #599.

Since no one has disputed my guess above so far, I'm going to take that to be the reality.

Closing as duplicate of #597.

@shurcooL apologies I missed this for some reason.

I'll make sure I look at this in #617 (comment)

4. Ensure we address #399

@myitcv, #597 (the issue this is a duplicate of) has already been resolved by #599.