To merge array of objects by property using JavaScript Lodash, we use the unionBy function.

For instance, we write

const original = [
  { label: "private", value: "[email protected]" },
  { label: "work", value: "[email protected]" },
];

const update = [
  { label: "private", value: "[email protected]" },
  { label: "school", value: "[email protected]" },
];

const result = _.unionBy(update, original, "label");

to call unionBy with the update and original arrays and merge the objects into one by matching the label property.

A new array with the merged objects is returned.