fillIn (dest, src) {
    utils.forOwn(src, function (value, key) {
      if (!Object.hasOwnProperty.call(dest, key) || dest[key] === undefined) {
        dest[key] = value
      }
    })
  }
Shallow copy own enumerable properties from `src` to `dest` that are on
`src` but are missing from `dest.

@example
import { utils } from 'js-data';
const a = { foo: 'bar', beep: 'boop' };
const b = { beep: 'bip' };
utils.fillIn(b, a);
console.log(b); // {"foo":"bar","beep":"bip"}

@method utils.fillIn
@param {object} dest The destination object.
@param {object} source The source object.
@see utils.deepFillIn
@see utils.deepMixIn
@since 3.0.0