old_contents: import React, { Component } from 'react'
  import { findDOMNode } from 'react-dom'
  import OptionContainer from './Option'
  
  export default class DropdownMenu extends Component {
    componentWillReceiveProps(nextProps) {
      this.scrollTo(this.props.highlightedIndex, nextProps.highlightedIndex)
    }
  
    componentDidMount() {
      this.optionsListOffsetHeight = this.optionsList.offsetHeight
      this.optionOffsetHeight = document.querySelector('.powerselect__option').offsetHeight
      this.scrollTo(0, this.props.highlightedIndex)
    }
  
    scrollTo(oldHighlightedIndex, newHighlightedIndex) {
      let optionOffsetHeight = this.optionOffsetHeight
      let delta = (optionOffsetHeight * newHighlightedIndex + optionOffsetHeight) - this.optionsListOffsetHeight
  
      if (delta > 0) {
        this.optionsList.scrollTop = delta
      } else {
        this.optionsList.scrollTop = 0
      }
    }
  
    render() {
      let {
        options,
        onOptionClick,
        handleKeyDown,
        selected,
        optionComponent,
        select,
        minWidth,
        highlightedIndex
      } = this.props
  
      let BeforeOptionsComponent = this.props.beforeOptionsComponent
      let AfterOptionsComponent = this.props.afterOptionsComponent
  
      return (
        <div
          tabIndex='1'
          className='powerselect__menu'
          onKeyDown={(event) => handleKeyDown(event, highlightedIndex)}
          style={{
            minWidth: `${minWidth}px`
          }}
        >
          {BeforeOptionsComponent && <BeforeOptionsComponent select={select} />}
          <div className='powerselect__options' ref={(optionsList) => this.optionsList = optionsList}>
            {
              options.map((option, idx) => (
                <OptionContainer
                  key={idx}
                  option={option}
                  select={select}
                  optionComponent={optionComponent}
                  isHighlighted={highlightedIndex === idx}
                  onOptionClick={() => {
                    onOptionClick(idx, option)}
                  }
                />
              ))
            }
          </div>
          {AfterOptionsComponent && <AfterOptionsComponent select={select} />}
        </div>
      )
    }
  }
  
new_contents: import React, { Component } from 'react'
  import { findDOMNode } from 'react-dom'
  import OptionContainer from './Option'
  
  export default class DropdownMenu extends Component {
    componentWillReceiveProps(nextProps) {
      this.scrollTo(nextProps.highlightedIndex)
    }
  
    componentDidMount() {
      this.optionsListOffsetHeight = this.optionsList.offsetHeight
      this.optionOffsetHeight = document.querySelector('.powerselect__option').offsetHeight
      this.scrollTo(this.props.highlightedIndex)
    }
  
    scrollTo(newHighlightedIndex) {
      let optionOffsetHeight = this.optionOffsetHeight
      let delta = (optionOffsetHeight * newHighlightedIndex + optionOffsetHeight) - this.optionsListOffsetHeight
  
      if (delta > 0) {
        this.optionsList.scrollTop = delta
      } else {
        this.optionsList.scrollTop = 0
      }
    }
  
    render() {
      let {
        options,
        onOptionClick,
        handleKeyDown,
        selected,
        optionComponent,
        select,
        minWidth,
        highlightedIndex
      } = this.props
  
      let BeforeOptionsComponent = this.props.beforeOptionsComponent
      let AfterOptionsComponent = this.props.afterOptionsComponent
  
      return (
        <div
          tabIndex='1'
          className='powerselect__menu'
          onKeyDown={(event) => handleKeyDown(event, highlightedIndex)}
          style={{
            minWidth: `${minWidth}px`
          }}
        >
          {BeforeOptionsComponent && <BeforeOptionsComponent select={select} />}
          <div className='powerselect__options' ref={(optionsList) => this.optionsList = optionsList}>
            {
              options.map((option, idx) => (
                <OptionContainer
                  key={idx}
                  option={option}
                  select={select}
                  optionComponent={optionComponent}
                  isHighlighted={highlightedIndex === idx}
                  onOptionClick={() => {
                    onOptionClick(idx, option)}
                  }
                />
              ))
            }
          </div>
          {AfterOptionsComponent && <AfterOptionsComponent select={select} />}
        </div>
      )
    }
  }
  
subject: Remove unused vars