allow array to be updated using obs.set

[mmckegg]

Currently obs.set simply falls back to observ's notify method, so if you call set on an observ-array everything just breaks. Trouble is, it appears to work, but the inner ._list is never updated. This behavior is not really ideal and quite confusing.

The new transaction method just about does what we want here, minus the initial shallow copy. This PR extracts out the update portion of transaction to a new obs.set method allowing the inner ._list to be updated using obs.set(rawList).

@Raynos I think this behavior of set makes more sense. What do you think?

[afandria]

I agree. Defining set directly on observ-array would make the API be more consistent.

I fell into the trap of using obsArray.set(rawArray). Some behaviors worked, but some methods such as getLength() were returning the wrong values.

[Raynos]

This PR implements a subset of #9

We want to support this.

[mmckegg]

Could really use this right now.

This PR doesn't support merging in nested observables (instead indices are overridden by the exact data set). This is tricky to support with arrays unless there's a way to uniquely identify the each element. The index isn't good enough as this moves around with splice operations.

This also means two-way databinding (at least with nesting) is not possible with this approach.

I seem to recall @Raynos discussing value only ObservArray (or was it Struct?). Maybe this obs.set would make more sense there.

@Raynos Shall we merge or should I fork?

[mmckegg]

Or maybe set would be better as a reinitializer? Essentially the same as creating a new ObservArray, throwing away the internal _list, and using the supplied one. Wouldn't get any diffing this way, but at least it would make the various obs.functions work as expected after an obs.set.

function set(array) {
    var obs = this
    obs.removeListeners.forEach(invoke)
    obs.removeListeners = list.map(function (observ) {
        return typeof observ === "function" ?
            addListener(obs, observ) :
            null
    })
    obs._list = array

    var values = array.map(function(value){
        return typeof value === "function" ? value() : value
    })

    obs._observSet(values)
}

[Raynos]

lgtm, feel free to merge.

We need a better way of doing .set()

[mmckegg]

@Raynos I don't seem to have npm publish rights. Can you publish this for me? I guess we should probably bump major.

[Raynos]

Published v3.0.0 :)