const doc2 = {
  "source": {
    "name": "foo",
    "event": "bar",
    "data": {
      "businessUnit": {
        "name": "baz"
      }
    }
  }
};

const pick1 = require('lodash.pick');
const pick2 = require('lodash/pick');

console.log('lodash.pick:', pick1(doc2, [
  'source.name',
  'source.event',
  'source.data.businessUnit.name'
]));

console.log('lodash/pick:', pick2(doc2, [
  'source.name',
  'source.event',
  'source.data.businessUnit.name'
]));