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【Q693】在 ts 中如何实现 Partial

在 ts 中如何实现 Partial

更多描述 实现 Partial,使得 Object 所有的属性变为可选属性。

PS: Partial 已经在 TS 中原生实现,见文档: https://www.typescriptlang.org/docs/handbook/utility-types.html#partialtype (opens in a new tab)

type User = {
  id: number;
  age: number;
  name: string;
};
 
// Output:
// type PartialUser = {
//   id?: number | undefined;
//   age?: number | undefined;
//   name?: string | undefined;
// }
type PartialUser = Partial<User>;

以下是使用案例

interface Todo {
  title: string;
  description: string;
}
 
function updateTodo(todo: Todo, fieldsToUpdate: Partial<Todo>) {
  return { ...todo, ...fieldsToUpdate };
}
 
const todo1 = {
  title: "organize desk",
  description: "clear clutter",
};
 
const todo2 = updateTodo(todo1, {
  description: "throw out trash",
});

Issue 欢迎在 Gtihub Issue 中回答此问题: Issue 714 (opens in a new tab)

Author 回答者: shfshanyue (opens in a new tab)

type Partial<T> = {
  [P in keyof T]?: T[P];
};