Question: difference between any and object without properties?

[joffrey-bion]

In the protocol definitions, I have seen occurrences of both type: "any" and type: "object" without any properties list.

What's the difference? Is it that any can be anything including primitives (effectively any JSON value) but object is limited to only structures with properties (effectively only JSON objects)?

In that case, does an object without properties list represent a type whose properties are unknown/dynamic?

In the typescript definitions, I noticed that most params of type object without properties are represented with the Headers interface, which is basically {[key: string]: string}. This would confirm my guess here. However, some are still translated into TS's any (e.g. PausedEvent.data), which is why I'm asking here.

[TimvdLippe]

As I read the .json file, the "type": "object" denote interfaces. For example,

devtools-protocol/json/browser_protocol.json

Line 603 in bc63f36

"type": "object",

maps to

devtools-protocol/types/protocol.d.ts

Line 2844 in bc63f36

export interface KeyframesRule {

The "type": "any" is used to denote values of an interface itself. I don't think there is any occurrence of "type": "object" of a value of an interface, is there?

[joffrey-bion]

I think I might have been unclear here. The general case of "type": "object" indeed represents interfaces, like the one you linked to here. For this purpose, "type": "object" goes along with "properties": [ ... ], which describes the properties of the interface.

In this question, I am specifically talking about places where "type": "object" is used without any "properties": [...] along with it. For instance:

devtools-protocol/json/js_protocol.json

Line 1090 in bc63f36

"type": "object"

That's an occurrence of a type object as a parameter of an event. It's not a reference to an existing interface declared as top-level domain type. But it's ok because it has no properties (so we're not in a situation like #244). So I guess what this means here is that it's a JSON object but without details about what properties are available.

The only difference I can imagine with "type": "any" is that I guess any could represent any sort of JSON element (primitives, arrays, objects), while "type": "object" could only represent actual JSON objects ({ ... }).

[TimvdLippe]

Ah I see, I had missed the usage in js_protocol.pdl. I have asked internally for clarification on this.

[joffrey-bion]

No problem, I was also confused when I searched browser_protocol and didn't find my examples anymore :D Took me a moment to realize it was in the other file.

Thanks a lot for asking around!

[caseq]

@joffrey-bion, you're reading it right -- "type": "any" implies any type at all, including primitive types such as boolean/numer/string, while "type": "object" implies a JSON object (i.e. a dictionary with string keys and values of "any" type).