epam/miew

import React from 'react'

const style = {
  width: '25px'
}

export default class SpeedButton extends React.Component {
  onChange(_event) {
    if (this.props.viewer) {
      const value =
        this.props.viewer.get(this.props.prefName) + this.props.delta
      if (!Number.isNaN(value)) {
        this.props.viewer.set(this.props.prefName, value)
      }
    }
  }

  render() {
    return (
      <button style={style} onClick={() => this.onChange()}>
        {' '}
        {this.props.delta > 0 ? '+' : '-'}{' '}
      </button>
    )
  }
}