A proposed solution to the problem of overwriting configurations

[Merott]

As you mentioned in the Wiki, currently there is no functionality to completely overwrite a configuration object or value. I'm proposing a solution, which if you accept, I'll happily submit a PR for.

I'm proposing the following syntax for completely overwriting/replacing a configuration:

"tasks": {
   "karma": {
      "single-run": {
         "(replace)browsers": [
            "Firefox"
         ]
      }
   }
}

A small change in deepmerge.js makes this possible: Merott@9ff0818

Object.keys(src).forEach(function (key) {
    if(key.indexOf('(replace)') === 0) {
        dst[key.substr(9)] = src[key];
    }
    else if (typeof src[key] !== 'object' || !src[key]) { ...

Do you see any problems with that approach?

[joshdmiller]

You're right - this is much cleaner than my ideas. We would obviously have to create a fork of the deep merge library (it's in there temporarily because the author can't push a bug fix needed by Warlock until his npm permissions get reset).

The only thing I might change is the syntax itself. Maybe something shorter like just "r" or "ow" (overwrite). We could also just pick a shorthand character sequence like ^, which is unlikely to be used as a key:

{
"tasks": {
   "karma": {
      "single-run": {
         "^browsers": [ "..." ]
      }
   }
}

Anyway, great idea!!!

[Merott]

I prefer ^

I also originally considered using ^, and the only reason I didn't use it was that I thought being a little more explicit with (replace) would make the syntax easier to understand. I have no real objection to ^ though, so I'd be happy with either of them.

[joshdmiller]

I prefer ^ too. I normally opt for clarity too, but in this case the aesthetics on the shorthand win me over. It's just easier to read for me. If you'd like to submit a PR, that'd be awesome!

However, we probably don't want to just change deepmerge.js as it'll be harder to merge upstream changes. Perhaps we should fork it and create a warlock-deepmerge library we can throw on npm. We can then add a test case for that change too since we don't have unit testing on Warlock proper - yet (see #4). Then we get the added bonus of removing deepmerge.js from the Warlock repo.

What do you think?

[Merott]

Good plan. I'll write a test case for it and submit a PR to warlock-deepmerge.

[joshdmiller]

warlock-deepmerge has the change and all is groovy.