Question

考虑方法update(documentRef, dataOrField, …preconditionOrValues) → {Transaction}。

我需要能够传递多对（FieldPath，Value），因为我需要一次更新几个字段。可以这样写：

txn.update(docRef,
  'field1', value1,
  'field2', value2
);

Typescript提供了UpdateData类型：

  /**
   * Update data (for use with `DocumentReference.update()`) consists of field
   * paths (e.g. 'foo' or 'foo.baz') mapped to values. Fields that contain dots
   * reference nested fields within the document.
   */
  export type UpdateData = {[fieldPath: string]: any};

并且updateData method signature被声明为：

    /**
     * Updates fields in the document referred to by the provided
     * `DocumentReference`. The update will fail if applied to a document that
     * does not exist.
     *
     * Nested fields can be updated by providing dot-separated field path
     * strings.
     *
     * @param documentRef A reference to the document to be updated.
     * @param data An object containing the fields and values with which to
     * update the document.
     * @param precondition A Precondition to enforce on this update.
     * @return This `Transaction` instance. Used for chaining method calls.
     */
    update(documentRef: DocumentReference<any>, data: UpdateData,
           precondition?: Precondition): Transaction;

现在，假设我有很多字段更新，例如：

  const fieldUpdates: FirebaseFirestore.UpdateData[] = [
    { ['field1']: value1 },
    { ['field2']: value2 },
  ];

如何将其传递给update方法？以下内容：

txn.update(docRef, ...fieldUpdates);

失败：

Expected at least 2 arguments, but got 1 or more.ts(2557)
firestore.d.ts(378, 49): An argument for 'data' was not provided.

Answer 1

只需传递一个带有字段名称和值的对象即可更新。

txn.update(docRef, {
    field1: value1,
    field2: value2
})

在TypeScript中，{[fieldPath: string]: any}的意思是“对象的属性必须是字符串，并且其值可以是任何值”。在这种情况下，它们的键是要更新的字段的路径。

如何使用强类型的UpdateData类型

1 个答案: