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Lodash _.defaultsDeep

Overview

The lodash _.defaultsDeep method is a utility function that helps in merging the properties of multiple objects. It takes in two or more objects and combines their properties recursively, creating a merged object that has all the properties of the original objects. If there are any property conflicts, it will retain the values of the first object provided.

Here is a syntax example:

_.defaultsDeep(object, [sources])

The first argument is the destination object and the remaining arguments are the source objects to merge. It works by recursively merging objects with the same property names, using the default value from the first object in case of a property conflict.

Here is an example of how to use _.defaultsDeep method in JavaScript:

const _ = require('lodash');

const object1 = {
  a: {
    b: 1,
    c: {
      d: 2,
    },
  },
};
const object2 = {
  a: {
    b: 3,
    c: {
      e: 4,
    },
  },
};

const result = _.defaultsDeep(object1, object2);

console.log(result);

In this example, defaultsDeep merges object2 into object1. The resulting merged object is:

{
  a: {
    b: 1,
    c: {
      d: 2,
      e: 4,
    },
  },
}

_.defaultsDeep method can be useful in many situations, such as combining default settings with user-defined options or merging JSON configuration files. It is a powerful utility function that can simplify many programming tasks that involve merging multiple objects.