adding-event-listeners.js

// Option A
window.addEventListener('touchstart', strike)
window.addEventListener('mousedown', strike)

window.addEventListener('touchmove', slide)
window.addEventListener('mousemove', slide)

window.addEventListener('touchend', release)
window.addEventListener('mouseup', release)

document.querySelector('select').addEventListener(
  'change',
  event => oscillator.type = event.target.value
)

document.querySelector('[type="range"]').addEventListener(
  'input',
  event => volume = event.target.value
)

// Option B
[
  {
    target: window,
    event: 'touchstart',
    action: strike
  },
  {
    target: window,
    event: 'mousedown',
    action: strike
  },
  {
    target: window,
    event: 'touchmove',
    action: slide
  },
  {
    target: window,
    event: 'mousemove',
    action: slide
  },
  {
    target: window,
    event: 'touchend',
    action: release
  },
  {
    target: window,
    event: 'mouseup',
    action: release
  },
  {
    target: document.querySelector('select'),
    event: 'change',
    action: event => oscillator.type = event.target.value
  },
  {
    target: document.querySelector('[type="range"]'),
    event: 'input',
    action: event => volume = event.target.value
  }
].forEach(action => 
  action.target.addEventListener(action.event, action.action)
)