isPlainObject usage blocks objects with prototype

[bpostlethwaite]

@etpinard @alexcjohnson re: an internal conversation.

The Plotly.js usage of isPlainObject appears to prevent objects with a prototype. This doesn't seem to be target behaviour of isPlainObject as Plotly.js seems to only care if the object behaves like an object (duck typing). Allowing prototype objects will make it easier for people to integrate Plotly.js with Typescript among other potential use cases.

@alexcjohnson made the note that it would be best to change the name of the function.

This issue has been encountered by teams actively integrating Plotly.js with a Typescript application.

[etpinard]

maybe switching to is-plain-obj would solve this issue.

[alexcjohnson]

maybe switching to is-plain-obj would solve this issue.

doesn't look like it - is-plain-obj explicitly looks for prototype to be missing. I notice though that we are already including it at least via color-parse - I wonder if we will need to alter this behavior all the way down our dep tree? that could be painful...

I don't think there's anything wrong with omitting the prototype check - hey, it works for imagetest, right? I imagine people could find a way to construct something that would cause errors, but in general it seems like simple prototyped objects work fine in our framework, and they seem to JSON.stringify fine for portability too. If we can write some end-to-end tests with some of the prototyped objects people really want to use I'd be OK with just loosening up the condition.

[jefshe]

Non-standard use case, but this also prevents plain javascript objects being passed into an iframe from working as well

[alexcjohnson]

Closing as #5151 is a more up-to-date duplicate