Method _getCueIndex

external/.scrollLibs.js:16724–16729

()

    }
  }
  _getCueIndex() {
    // StringMap<int> {cue: index}
    // When there are multiple tails with the same cue, index stores the last content.
    // todo: change the above behavior: when a collision occurs, create an array.
    return this._cueIndex || this._makeCueIndex()
  }
  getContentsArray() {
    return this.map(particle => particle.content)
  }