code: function(array) {
      this.destination = this.parse(array)
  
      // normalize length of arrays
      if (this.value.length != this.destination.length) {
        var lastValue       = this.value[this.value.length - 1]
          , lastDestination = this.destination[this.destination.length - 1]
  
        while(this.value.length > this.destination.length)
          this.destination.push(lastDestination)
        while(this.value.length < this.destination.length)
          this.value.push(lastValue)
      }
  
      return this
    }
docs: Make array morphable