Get the differences between two similar objects, like a git diff

get-differences.ts

import {isEqual, transform, isObject} from 'lodash';


interface Diff {
  base: any;
  comparison: any;
}
/**
 * Get the differences between two objects.
 * @param base - The base object.
 * @param comparison - The comparison object.
 * @returns The differences between the two objects.
 */
function getDifferences(
  base: Object,
  comparison: Object,
): Diff | 'No differences found' {
  const diffs: Diff = {
    base: {},
    comparison: {},
  };

  transform(
    base,
    (result, value, key) => {
      if (!isEqual(value, comparison[key])) {
        if (isObject(value) && isObject(comparison[key])) {
          const nestedDiffs = getDifferences(value, comparison[key]);
          if (nestedDiffs !== 'No differences found') {
            result.base[key] = nestedDiffs.base;
            result.comparison[key] = nestedDiffs.comparison;
          }
        } else {
          result.base[key] = value;
          result.comparison[key] = comparison[key];
        }
      }
    },
    diffs,
  );

  return Object.keys(diffs.base).length === 0 ? 'No differences found' : diffs;
}

const obj1 = { a: 1, b: { c: 2, d: 3 }, e: 4 }
const obj2 = { a: 1, b: { c: 2, d: 5 }, e: 6 }


 console.log(getDifferences(obj1, obj2));

// Outputs:
//
// {
//   base: { 
//     b: { d: 3 }, 
//     e: 4 
//   },
//   comparison: { 
//     b: { d: 5 }, 
//     e: 6 
//   }
// }