TypeScript 无法编译 Mongoose 查询助手

Question

我正在开发一个使用 Mongoose 并使用

tsc

进行编译的 TypeScript 项目。当我尝试使用带有

.find()

的查询助手时：

import { InferRawDocType, Schema, model } from "mongoose";

export const mySchemaDefinition = {
  key: "string",
  value: "string"
} as const;
export type RawSchema = InferRawDocType<typeof mySchemaDefinition>;
export const mySchema = new Schema(mySchemaDefinition, {
  query: {
    byKey: function (key: string) {
      return this.where({ key: key });
    }
  }
});
export const MyModel = model("MyModel", mySchema);

MyModel.find({ key: "123" }).exec(); // OK
MyModel.findOne().byKey("123").exec(); // OK
MyModel.find().byKey("123").exec(); // Error

TypeScript 在转译过程中抛出错误：

The 'this' context of type 'QueryWithHelpers<(Document<unknown, { byKey: <T extends Query<unknown, Document<unknown, {}, FlatRecord<{ readonly key: "string"; readonly value: "string"; }>> & FlatRecord<{ readonly key: "string"; readonly value: "string"; }> & { _id: ObjectId; } & { __v: number; }, {}, FlatRecord<{ readonly key: "string"; readonly value: "string"; }>, "find", Record<string, never>>>(this: T, key: string) => T; }, { readonly key: "string"; readonly value: "string"; }> & { readonly key: "string"; readonly value: "string"; 
} & { _id: ObjectId; } & { __v: number; })[], Document<unknown, { byKey: <T extends Query<unknown, Document<unknown, {}, FlatRecord<{ readonly key: "string"; readonly value: "string"; }>> & FlatRecord<{ readonly key: "string"; readonly value: "string"; }> & { _id: ObjectId; } & { __v: number; }, {}, FlatRecord<{ readonly key: "string"; readonly value: "string"; }>, "find", Record<string, never>>>(this: T, key: string) => T; }, { readonly key: "string"; readonly value: "string"; }> & { readonly key: "string"; readonly value: "string"; } & { _id: ObjectId; } & { __v: number; }, { byKey: <T extends Query<unknown, Document<unknown, {}, FlatRecord<{ readonly key: "string"; readonly value: "string"; }>> & FlatRecord<{ readonly key: "string"; readonly value: "string"; }> & { _id: ObjectId; } & { __v: number; }, {}, FlatRecord<{ readonly key: "string"; readonly value: "string"; }>, "find", Record<string, never>>>(this: T, key: string) => T; }, { readonly key: "string"; readonly value: "string"; }, "find", {}>' is not assignable to method's 'this' of type 'Query<unknown, Document<unknown, {}, FlatRecord<{ readonly key: "string"; readonly value: "string"; 
}>> & FlatRecord<{ readonly key: "string"; readonly value: "string"; }> & { _id: ObjectId; } & { __v: number; }, {}, FlatRecord<{ readonly key: "string"; readonly value: "string"; }>, "find", Record<string, never>>'.
  The types returned by 'lean(...).exec()' are incompatible between these types.
    Type 'Promise<({ readonly key: "string"; readonly value: "string"; } & { _id: ObjectId; } & { __v: number; })[]>' is not assignable to type 'Promise<{ readonly key: "string"; readonly value: "string"; } & { _id: ObjectId; } & { __v: number; }>'.
      Type '({ readonly key: "string"; readonly value: "string"; } & { _id: ObjectId; } & { __v: number; })[]' is not assignable to type '{ readonly key: "string"; readonly value: "string"; } & 
{ _id: ObjectId; } & { __v: number; }'.
        Type '({ readonly key: "string"; readonly value: "string"; } & { _id: ObjectId; } & { __v: number; })[]' is missing the following properties from type '{ readonly key: "string"; readonly value: "string"; }': key, value

但它只发生在

.find

，

.findOne

工作正常。

this

上下文似乎是正确的类型。
这是

tsc

配置的问题还是有我可以修复的 Mongoose 类型错误？

构建命令：

tsc index.ts --esModuleInterop --outDir ./build --noErrorTruncation

tsconfig.json

（主要针对同一项目中的 React 应用程序）：

{
  "compilerOptions": {
    "target": "es5",
    "lib": ["dom", "dom.iterable", "esnext"],
    "allowJs": true,
    "skipLibCheck": true,
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true,
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "noFallthroughCasesInSwitch": true,
    "module": "esnext",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "noEmit": true,
    "jsx": "react-jsx"
  },
  "include": ["src"]
}

Answer 1

发生错误的原因是 byKey 查询助手的类型不正确，无法同时处理 find() 和 findOne() 操作。当前的实现假定单个文档返回类型，但 find() 返回一个数组。让我们修复打字：

export const mySchemaDefinition = {
  key: "string",
  value: "string"
} as const;
export const mySchema = new Schema(mySchemaDefinition, {
query: {
byKey: function<T extends Query<any, any>>(this: T, key: string) {
 return this.where({ key: key });
    }
  }
});

此更改使得 byKey 查询助手足够通用，可以与 find() 和 findOne() 操作一起使用。