Allow append to existing object; allow user-provided read/write functions

[derrell]

The following changes are included here:

1. New Method: append

A new append method has been added. Whereas the traditional calls such as

store.set('a', { b : c });
store.set('a', { d : e });

allows the second call to overwrite the entire value of 'a', yielding

{
  d : e
}

this sequence:

store.append('a', { b : c });
store.append('a', { d : e });

ratains prior values, and thus yields:

{
  b : c,
  d : e
}

2. The means of reading (and parsing), and writing to files can now be
   overridden by the caller, in the options argument. This allows adding
   additional error handling, in the simple case, or reading and writing entirely
   different types of files in the more sophisticated case. An example is
   provided in examples/ini.js that shows the store reading and writing an INI
   file, while allowing it to be manipulated programmatically in the standard
   data-store fashion.

[doowb]

Thanks for the PR. Depending on @jonschlinkert feedback, I like this idea. I'm requesting a few changes and have a few questions in this review. Also, please add tests for the new options.

[derrell]

I don't know mocha well enough (or at all, other than by inspection of existing tests) to be able to add tests for the new options. That requires not doing the beforeEach section, where the store is automatically created, and instead doing one or more of those with the new options. I think I'll have to leave those tests to someone who knows this test infrastructure. The examples/ini.js shows it working and could possibly be used as a template for tests.

Otherwise, I think all questions have been answered and addressed. Hope you find this good to go.

Thanks.

[doowb]

@derrell thanks for the making the requested changes. I'll look at this over the weekend and try it out using the example code.

[derrell]

A friendly ping...

[doowb]

Sorry, I didn't get to this last weekend. I'll check it out this weekend.

[doowb]

@derrell sorry for the delay in getting to this. All of the changes I'm requesting here are linting changes to keep with the same syntax style of the project. Most of them I was able to use the "suggest" feature on GitHub, but there are a couple of multi-line changes that I wasn't able to use that.

Thanks again, and I think this looks good after those nitpicks. I did pull this down to run the example and tests.

[derrell]

You got it! Yes, I always try to maintain style consistency with whatever code I'm editing, but habits are... well, they're habitual. :-)

All should be corrected now.

[doowb]

@derrell thanks, there are a still a few places with requested changes. (BTW... I made them granular because GitHub makes it easy to do single line "suggestions" and to resolve "outdated" conversations)

[derrell]

Sigh. Github covered those up with a "hidden conversations" that I didn't notice. I think all are now showing as outdated, so hopefully we're all set.

[doowb]

Thanks! Sorry for all the nitpicks, I'm going to merge this in and I'll get the version bumped and published today or tomorrow morning.

[derrell]

Thanks!

[derrell]

Hi. I've been using the source version to date, so hadn't noticed... It seems that the new version never got published?

[derrell]

@doowb Just a ping to see if you wanted to publish this latest version now that you've been given permission... Thanks.

[doowb]

@derrell I had realized that the set-value library allows passing in a merge option, but data-store wasn't handling options in a way that could be passed through. After talking about this with Jon, I implemented #35. The changes also allow passing through a custom merge function, which you can see in this test.

I'll be merging that PR in soon and publishing it to npm. There were also a few naming changes with the new options that you introduced. Thanks for your original PR and sorry for the delay in getting it published.

[derrell]

Thanks. Eagerly awaiting. It looks like examples/ini.js will need an update to the new naming scheme as well; it uses the names I had added.