Use web spec best practices

[zolkis]

Originally posted by @inexorabletash in #446 (comment)

Drive by comment: the first step here (If a or b is not an instance of MLOperand, then throw a "TypeError"...) is unnecessary, and I see this repeated throughout the newly introduced algorithms for methods ("operations" in Web IDL). The Web IDL bindings already take care validating input types and throwing TypeError.

Further, even in cases where an explicit error must be thrown, the intrinsic type TypeError should be thrown, not a DOMException of type "TypeError" (which is not present in https://webidl.spec.whatwg.org/#idl-DOMException-error-names)

(Issue created to document this change).

[inexorabletash]

Another example:

in constant() - If type is undefined, let type be "float32". - this is handled automatically by having the default in the Web IDL.

[inexorabletash]

Also (and this is not new), dictionary members are more normally references in prose using the infra ordered map syntax: options["foo"]

By the time an algorithm "sees" the dictionary, it's gone through the bindings layer and is an ordered map - https://webidl.spec.whatwg.org/#idl-dictionaries

[inexorabletash]

throw a "TypeError" simple exception

Just write: throw a TypeError.

In bikeshed markdown:

... [=exception/throw=] a {{TypeError}}.

[inexorabletash]

And (this new is in PR 446) the entire "check linear options" algorithm is unnecessary; the dictionary bindings for ECMAScript take care of all of that, including default values.

[inexorabletash]

(apologies for random feedback; I may have more time later this week to do a more thorough pass)

[inexorabletash]

Not new: In "create MLActivation" steps

If name is undefined or null, throw a "TypeError" and abort these steps.

It looks like all call sites are internal to the spec and so this could just be an assert.

And this is more off topic, but: none of the call sites for "create MLActivation" actually pass builder - that should be fixed at the call sites. I also don't see any of the call sites passing init-steps but maybe I'm missing something.

[inexorabletash]

Not new: in input(name, descriptor):

If name is undefined or an empty string, then throw a TypeError and stop.

name is defined as DOMString; passing literal undefined from script will yield the string "undefined". So this can be reduced to just a test for an empty string.

(This is a gotcha for web developers since an error would be better, but that's how the Web IDL bindings work.)

[inexorabletash]

Not new: in conv2d(input, filter, options)

If options is undefined, let options be an empty object.

The options argument is defined as optional MLConv2dOptions options = {} so it will always be present.

If options.padding is undefined, ...

It's more correct to write:

If options["padding"] exists, ...

in Bikeshed markdown:

If |options|[{{MLConv2dOptions/"padding"}}] [=map/exists=] ...

[inexorabletash]

Not new:

Let ... be the first argument.
Let ... be the second argument.

This is unnecessary, arguments are named. I see 5 uses of "first argument", and 2 of "second argument". Just drop these.