Skip to content

docs(mapping): remove extra bracket #149

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
dogledogle wants to merge 1 commit into
base: main
Choose a base branch
from
+1 −1
Open

docs(mapping): remove extra bracket #149

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion docs/mapping.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -320,7 +320,7 @@ type FilteredUser = Filter<User> // { name: string }

上面示例中，映射`K in keyof T`获取类型`T`的每一个属性以后，然后使用`as Type`修改键名。

它的键名重映射`as T[K] extends string ? K : never]`，使用了条件运算符。如果属性值`T[K]`的类型是字符串，那么属性名不变，否则属性名类型改为`never`，即这个属性名不存在。这样就等于过滤了不符合条件的属性，只保留属性值为字符串的属性。
它的键名重映射`as T[K] extends string ? K : never`，使用了条件运算符。如果属性值`T[K]`的类型是字符串，那么属性名不变，否则属性名类型改为`never`，即这个属性名不存在。这样就等于过滤了不符合条件的属性，只保留属性值为字符串的属性。

### 联合类型的映射

Expand Down