For a long time I was thinking that

_.extend({}, obj) is the same as _.cloneDeep(obj)

in lodash.

But I found out that object, created with extend function has the same __proto__ hash, unlike object, created with cloneDeep function.

---

Please, explain what is the difference between Lodash's cloneDeep and extend({},?

For a long time I was thinking that

_.extend({}, obj) is the same as _.cloneDeep(obj)

in lodash.

But I found out that object, created with extend function has the same __proto__ hash, unlike object, created with cloneDeep function.

---

Please, explain what is the difference between Lodash's cloneDeep and extend({},?

• javascript
• object
• prototype
• lodash
• extend

Share Improve this question Follow asked Feb 12, 2016 at 15:01 James AkwuhJames Akwuh 2,21722 gold badges2424 silver badges2525 bronze badges 0

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1 Answer 1

Sorted by: Reset to default 4

The key difference is cloneDeep returns a new object while extend mutates the object in place.

var a = {x: 1};
_.extend(a, {}) === a // true
_.cloneDeep(a) === a // false

In your example:

_.extend({}, a) === a // false
_.cloneDeep(a) === a // false

what you are extending is not a, but the empty object {}. So when you strictly pare the result of _.extend({}, a) with a, you are paring an extended empty object. When you are paring _.cloneDeep(a) with a, you are paring a clone of a with itself. Thus, they may give the same result, but the nature is different.