git ssb

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var Value = require('./value')
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var LazyWatcher = require('./lib/lazy-watcher')
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var isSame = require('./lib/is-same')
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var isObservable = require('./is-observable')
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var resolve = require('./resolve')
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var addCollectionMethods = require('./lib/add-collection-methods')
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var forEach = require('./for-each')
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module.exports = Array
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function Array (defaultValues, opts) {
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  var object = []
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  var sources = []
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  var releases = []
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  var fixedIndexing = opts && opts.fixedIndexing || false
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  var comparer = opts && opts.comparer || null
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  var binder = LazyWatcher(update, listen, unlisten)
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  binder.value = object
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  if (defaultValues && defaultValues.length) {
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    forEach(defaultValues, add)
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  }
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  var observable = function MutantArray (listener) {
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    if (!listener) {
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      return binder.getValue()
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    }
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    return binder.addListener(listener)
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  }
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  // getLength, get, indexOf, etc
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  addCollectionMethods(observable, sources)
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  observable.push = function (item) {
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    var result = null
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    if (arguments.length === 1) {
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      result = add(item)
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    } else {
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      result = []
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      for (var i = 0; i < arguments.length; i++) {
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        result.push(add(arguments[i]))
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      }
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    }
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    binder.broadcast()
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    return result
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  }
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  observable.put = function (index, valueOrObs) {
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    valueOrObs = getObsValue(valueOrObs)
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    sources[index] = valueOrObs
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    object[index] = resolve(valueOrObs)
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    if (binder.live) {
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      tryInvoke(releases[index])
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      releases[index] = bind(valueOrObs)
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    }
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    binder.broadcast()
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    return valueOrObs
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  }
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  observable.insert = function (valueOrObs, at) {
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    valueOrObs = getObsValue(valueOrObs)
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    sources.splice(at, 0, valueOrObs)
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    if (binder.live) releases.splice(at, 0, bind(valueOrObs))
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    object.splice(at, 0, resolve(valueOrObs))
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    binder.broadcast()
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    return valueOrObs
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  }
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  observable.pop = function () {
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    var result = sources.pop()
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    if (binder.live) tryInvoke(releases.pop())
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    object.pop()
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    binder.broadcast()
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    return result
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  }
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  observable.shift = function () {
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    var result = sources.shift()
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    if (binder.live) tryInvoke(releases.shift())
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    object.shift()
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    binder.broadcast()
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    return result
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  }
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  observable.clear = function () {
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    releases.forEach(tryInvoke)
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    sources.length = 0
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    releases.length = 0
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    object.length = 0
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    binder.broadcast()
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  }
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  observable.delete = function (valueOrObs) {
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    observable.deleteAt(sources.indexOf(valueOrObs))
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  }
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  observable.deleteAt = function (index) {
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    if (index >= 0 && index < sources.length) {
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      sources.splice(index, 1)
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      if (binder.live) releases.splice(index, 1).forEach(tryInvoke)
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      object.splice(index, 1)
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      binder.broadcast()
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    }
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  }
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  observable.transaction = function (cb) {
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    binder.transaction(observable, cb)
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  }
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  observable.set = function (values) {
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    if (fixedIndexing) {
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      var length = values && values.length || 0
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      for (var i = 0; i < length; i++) {
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        if (!sources[i]) {
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          var valueOrObs = getObsValue(values[i])
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          sources[i] = valueOrObs
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          object[i] = resolve(valueOrObs)
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          if (binder.live) {
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            releases[i] = bind(valueOrObs)
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          }
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        } else {
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          sources[i].set(values[i])
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        }
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      }
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      for (var index = length; index < sources.length; index++) {
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        tryInvoke(releases[index])
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      }
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      releases.length = length
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      sources.length = length
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      object.length = length
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      binder.broadcast()
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    } else {
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      unlisten()
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      sources.length = 0
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      releases.length = 0
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      object.length = 0
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      forEach(values, add)
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      if (binder.live) {
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        listen()
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        binder.broadcast()
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      }
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    }
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  }
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  return observable
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  // scoped
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  function getObsValue (valueOrObs) {
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    if (fixedIndexing && !isObservable(valueOrObs)) {
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      valueOrObs = Value(valueOrObs)
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    }
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    return valueOrObs
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  }
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  function add (valueOrObs) {
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    valueOrObs = getObsValue(valueOrObs)
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    sources.push(valueOrObs)
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    object.push(resolve(valueOrObs))
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    if (binder.live) {
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      releases.push(bind(valueOrObs))
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    }
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    return valueOrObs
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  }
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  function bind (valueOrObs) {
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    return typeof valueOrObs === 'function' ? valueOrObs(binder.onUpdate) : null
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  }
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  function listen () {
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    sources.forEach(function (obs, i) {
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      releases[i] = bind(obs)
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    })
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  }
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  function unlisten () {
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    releases.forEach(tryInvoke)
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    releases.length = 0
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  }
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  function update () {
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    var changed = false
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    sources.forEach(function (source, i) {
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      var newValue = resolve(source)
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      if (!isSame(newValue, object[i], comparer)) {
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        object[i] = newValue
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        changed = true
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      }
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    })
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    return changed
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  }
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}
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function tryInvoke (func) {
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  if (typeof func === 'function') {
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    func()
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  }
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}
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