mattphillips/detailedDiffDeletedToNull.js

## detailedDiffDeletedToNull.js
// this is an example of what may be returned by the detailedDiff function
const detailedDifference = {
  added: {
    matt: 'phillips',
  },
  updated: {
    hello: 'world',
  },
  deleted: {
    a: {
      b: {
        c: undefined,
      },
      d: undefined,
    },
    e: undefined,
  },
};

// this function is written in es6. if you are using es5 then just change `() => { }` to be `function () { }`
// it takes the deleted object and turns the undefined values into null (or another value just change the null on line 25)
const mapUndefinedToNull = (deleted) => {
  return Object.keys(deleted).reduce((acc, key) => {
    if (deleted[key] === undefined) {
      return Object.assign({}, acc, { [key]: null });
    }

    return Object.assign({}, acc, { [key]: mapUndefinedToNull(deleted[key]) });
  }, {});
};

const detailedDifferenceWithNulls = Object.assign({}, detailedDifference, { deleted: mapUndefinedToNull(detailedDifference.deleted) });

console.log(JSON.stringify(detailedDifferenceWithNulls, null, 2)); // logs:
/*
{
  "add": {
    "matt": "phillips"
  },
  "updated": {
    "hello": "world"
  },
  "deleted": {
    "a": {
      "b": {
        "c": null
      },
      "d": null
    },
    "e": null
  }
}
*/