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 resolve = require('./resolve')
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var isObservable = require('./is-observable')
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var forEachPair = require('./for-each-pair')
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var addLookupMethods = require('./lib/add-lookup-methods')
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module.exports = Dict
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function Dict (defaultValues, opts) {
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  var object = Object.create({})
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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) {
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    forEachPair(defaultValues, put)
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  }
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  var observable = function MutantDictionary (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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  addLookupMethods(observable, sources)
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  observable.put = function (key, valueOrObs) {
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    valueOrObs = getObsValue(valueOrObs)
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    put(key, valueOrObs)
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    binder.broadcast()
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    return valueOrObs
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  }
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  observable.clear = function () {
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    Object.keys(sources).forEach(function (key) {
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      tryInvoke(releases[key])
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      delete sources[key]
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      delete releases[key]
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      delete object[key]
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    })
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    binder.broadcast()
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  }
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  observable.delete = function (key) {
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    tryInvoke(releases[key])
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    delete sources[key]
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    delete releases[key]
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    delete object[key]
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    binder.broadcast()
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  }
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  observable.includes = function (valueOrObs) {
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    return !!~object.indexOf(valueOrObs)
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  }
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  observable.set = function (values) {
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    if (fixedIndexing) {
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      var keys = []
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      forEachPair(values, function (key, value) {
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        keys.push(key)
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        if (sources[key]) {
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          sources[key].set(value)
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        } else {
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          put(key, getObsValue(value))
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        }
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      })
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      Object.keys(sources).forEach(function (key) {
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        if (!keys.includes(key)) {
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          tryInvoke(releases[key])
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          delete sources[key]
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          delete releases[key]
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          delete object[key]
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        }
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      })
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    } else {
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      Object.keys(sources).forEach(function (key) {
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        tryInvoke(releases[key])
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        delete sources[key]
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        delete releases[key]
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        delete object[key]
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      })
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      forEachPair(values, put)
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      binder.broadcast()
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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 put (key, valueOrObs) {
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    tryInvoke(releases[key])
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    sources[key] = valueOrObs
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    if (binder.live) {
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      releases[key] = bind(key, valueOrObs)
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    }
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    object[key] = resolve(valueOrObs)
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  }
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  function bind (key, valueOrObs) {
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    return typeof valueOrObs === 'function' ? valueOrObs(updateKey.bind(this, key)) : null
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  }
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  function updateKey (key, value) {
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    object[key] = value
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    binder.broadcast()
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  }
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  function listen () {
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    Object.keys(sources).forEach(function (key) {
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      releases[key] = bind(sources[key])
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    })
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  }
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  function unlisten () {
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    Object.keys(sources).forEach(function (key) {
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      tryInvoke(releases[key])
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      delete releases[key]
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    })
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  }
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  function update () {
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    var changed = false
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    Object.keys(sources).forEach(function (key) {
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      var newValue = resolve(sources[key])
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      if (!isSame(newValue, object[key], comparer)) {
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        object[key] = 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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