How to use

_pick

function

in

lodash

/**
  * Fetch the ID of a channel matched by type and channel data filter
  *
  * @param {string} type - channel type
  * @param {object} filter - to be matched against channel data
  * @returns {number} channelID
  */
 getDataChannelId (type, filter) {
  return Object
   .keys(this._channelMap)
   .find(cid => {
    const c = this._channelMap[cid]
    const fv = _pick(c, Object.keys(filter))
    return c.channel === type && _isEqual(fv, filter)
   })
 }

const fv = _pick(msg, Object.keys(sub[1]))