js lodash merge 2 arrays of object by key

lodash_merge_by_key.js

// Source reference: https://stackoverflow.com/questions/38612972/how-to-merge-two-array-of-object-by-using-lodash

_.mixin({
  mergeByKey(arr1, arr2, key) {
    const criteria = {};
    criteria[key] = null;
    return _.map(arr1, (item) => {
      criteria[key] = item[key];
      return _.merge(item, _.find(arr2, criteria));
    });
  },
});

// Example
const array1 = [
  { a: 3, b: 3 },
  { a: 5, b: 5 },
];
const array2 = [{ b: 3 }, { b: 4 }, { b: 5 }];

console.log(_.mergeByKey(array2, array1, 'b'));
// => [ { b: 3, a: 3 }, { b: 4 }, { b: 5, a: 5 } ]