Add function for deep merge? about seamless-immutable

[rtfeldman]

I dig it! Test duplication is no problem, but from an API perspective I'd prefer if this were an optional boolean passed to merge to enable deep merging.

Would love to see a Pull Request for this. 👍

[crudh]

Ok! Instead of a boolean, what to you think about a mergeWith function or similar that takes a config object first (which the normal merge can use under the covers) so more config can be added later if needed?

obj1.mergeWith({deep: true}, obj2);

I have a use case where I would like to supply a custom merger sometimes, that could fit into this strategy.

But if you don't like it I will do a PR with the boolean.

[RangerMauve]

IMO it's usually nicer to have configs or optional flags as the last argument in a function and not the first.

[crudh]

@RangerMauve I agree in general, but if the With in the function name is for merging with the config I think it is natural if the mandatory config is first. Especially if it is a merge with multiple objects like:

obj1.mergeWith({deep: true}, obj2, obj3, obj4, obj5);

But it doesn't matter much either way. Any thoughts @rtfeldman?

[RangerMauve]

@crudh That's a good point, actually. And it'd work well once rest paramters become mainstream.

[rtfeldman]

Good points all around. My preference is to change the existing merge as follows:

1. It now always takes exactly one or exactly two arguments.
2. The first argument works the same as always: you can pass it one object to merge, or an array of them.
3. The second argument is optional, and is a configuration object that currently supports only {deep: true}

Sound good?

[crudh]

Sounds good to me!