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minor fixes

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Ilya Kantor 2021-02-02 11:43:35 +03:00
parent 19bf2d3f5a
commit 3fa4c32e1d
7 changed files with 32 additions and 23 deletions
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1-js/04-object-basics/07-optional-chaining/article.md
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@ -166,9 +166,9 @@ userGuest.admin?.(); // nothing (no such method)
*/!*
```
Here, in both lines we first use the dot (`user1.admin`) to get `admin` property, because the user object must exist, so it's safe read from it.
Here, in both lines we first use the dot (`userAdmin.admin`) to get `admin` property, because we assume that the user object exists, so it's safe read from it.
Then `?.()` checks the left part: if the admin function exists, then it runs (that's so for `user1`). Otherwise (for `user2`) the evaluation stops without errors.
Then `?.()` checks the left part: if the admin function exists, then it runs (that's so for `userAdmin`). Otherwise (for `userGuest`) the evaluation stops without errors.
The `?.[]` syntax also works, if we'd like to use brackets `[]` to access properties instead of dot `.`. Similar to previous cases, it allows to safely read a property from an object that may not exist.