text: import DirectedEdge from '../../planargraph/DirectedEdge'
  import Assert from '../../util/Assert'
  
  export default class LineMergeDirectedEdge extends DirectedEdge {
    constructor () {
      const from = arguments[0]
      const to = arguments[1]
      const directionPt = arguments[2]
      const edgeDirection = arguments[3]
      super(from, to, directionPt, edgeDirection)
    }
    getNext () {
      if (this.getToNode().getDegree() !== 2) {
        return null
      }
      if (this.getToNode().getOutEdges().getEdges().get(0) === this.getSym()) {
        return this.getToNode().getOutEdges().getEdges().get(1)
      }
      Assert.isTrue(this.getToNode().getOutEdges().getEdges().get(1) === this.getSym())
      return this.getToNode().getOutEdges().getEdges().get(0)
    }
    interfaces_ () {
      return []
    }
    getClass () {
      return LineMergeDirectedEdge
    }
  }
  