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minor fixes

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This commit is contained in:
Ilya Kantor 2022-05-03 23:43:43 +04:00
parent 1dc862c333
commit 12024bc6b8
1 changed files with 3 additions and 3 deletions
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1-js/04-object-basics/02-object-copy/article.md
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@ -203,7 +203,7 @@ let user = {
alert( user.sizes.height ); // 182 alert( user.sizes.height ); // 182
``` ```
Now it's not enough to copy `clone.sizes = user.sizes`. `user.sizes` is an object, and will be copied by reference, so `clone` and `user` will share the same sizes: Now it's not enough to copy `clone.sizes = user.sizes`, because `user.sizes` is an object, and will be copied by reference, so `clone` and `user` will share the same sizes:
```js run ```js run
let user = { let user = {
@ -220,10 +220,10 @@ alert( user.sizes === clone.sizes ); // true, same object
// user and clone share sizes // user and clone share sizes
user.sizes.width++; // change a property from one place user.sizes.width++; // change a property from one place
alert(clone.sizes.width); // 51, see the result from the other one alert(clone.sizes.width); // 51, get the result from the other one
``` ```
To fix that, we should use a cloning loop that examines each value of `user[key]` and, if it's an object, then replicate its structure as well. That is called a "deep cloning". To fix that and make `user` and `clone` truly separate objects, we should use a cloning loop that examines each value of `user[key]` and, if it's an object, then replicate its structure as well. That is called a "deep cloning".
We can use recursion to implement it. Or, to not reinvent the wheel, take an existing implementation, for instance [_.cloneDeep(obj)](https://lodash.com/docs#cloneDeep) from the JavaScript library [lodash](https://lodash.com). We can use recursion to implement it. Or, to not reinvent the wheel, take an existing implementation, for instance [_.cloneDeep(obj)](https://lodash.com/docs#cloneDeep) from the JavaScript library [lodash](https://lodash.com).