array-sort.js

var applyPatch = require("./apply-patch.js")
var setNonEnumerable = require("./lib/set-non-enumerable.js")

module.exports = sort

function sort(compare) {
    var obs = this
    var list = obs._list.slice()

    var unpacked = unpack(list)

    var sorted = unpacked
            .map(function(it) { return it.val })
            .sort(compare)

    var packed = repack(sorted, unpacked)

    //fake diff - for perf
    //adiff on 10k items === ~3200ms
    //fake on 10k items === ~110ms
    var changes = [ [ 0, packed.length ].concat(packed) ]

    var valueChanges = changes.map(applyPatch.bind(obs, sorted))

    setNonEnumerable(sorted, "_diff", valueChanges)

    obs._observSet(sorted)
    return changes
}

function unpack(list) {
    var unpacked = []
    for(var i = 0; i < list.length; i++) {
        unpacked.push({
            val: ("function" == typeof list[i]) ? list[i]() : list[i],
            obj: list[i]
        })
    }
    return unpacked
}

function repack(sorted, unpacked) {
    var packed = []

    while(sorted.length) {
        var s = sorted.shift()
        var indx = indexOf(s, unpacked)
        if(~indx) packed.push(unpacked.splice(indx, 1)[0].obj)
    }

    return packed
}

function indexOf(n, h) {
    for(var i = 0; i < h.length; i++) {
        if(n === h[i].val) return i
    }
    return -1
}