How about:

_autoFocusModes: {
  MANUALLY_TRIGGERED: 'auto',
  CONTINUOUS_CAMERA: 'continuous-picture',
  CONTINUOUS_VIDEO: 'continuous-video'
},

...?

The underscores are to be consistent with the style used in the reset of the file.

To get the benefits of the symbolic constants, can I do this?

_autoFocusSupport: {
  this._autoFocusModes.MANUALLY_TRIGGERED: false,
  this._autoFocusModes.CONTINUOUS_CAMERA: false,
  this._autoFocusModes.CONTINUOUS_VIDEO: false
},

...?