打字稿扩展模块(扩展) [英] Typescript extend module (augmentation)

问题描述

我想用自己的类和函数扩展已安装的模块(猫鼬). 我写了函数和类，它们工作正常.

i want to extend a installed module (Mongoose) with my own class and function. I wrote the function and class and they work fine.

现在我想将它们添加到mongoose模块中. 所以我现在拥有的是这个文件: mongoInstance.ts

Now i wanted to add them to the mongoose module. So what i have now is this file: mongoInstance.ts

import * as mg from 'mongoose'

class _Schema extends mg.Schema {
    constructor(definition?: mg.SchemaDefinition, options?: mg.SchemaOptions) {
        super(definition, options)
        this.addData()
    }
    private addData() {
        //do stuff
    }
}  

function _limitedRequest(schema: mg.Schema, options = 200) {
    schema.pre("find", function (next) {
        this.limit(options)
        next()
    })
}

declare module 'mongoose' {
    export class _Schema extends Schema {
        constructor(definition?: SchemaDefinition, options?: SchemaOptions)
        private addData(): void
    }
    export function _limitedRequest(schema: Schema, options?: number): void
}

现在我可以在我的应用中的任何地方做

Now anywhere in my app i can do:

otherFile.ts

import * as mg from 'mongoose'
//doesnt work
var test1= new mg._Schema({})
//works
var test2= new mg.Schema({})

因此VSCode向我推荐了我的课程，并且IntellIsense起作用了.但是似乎没有该类的实现. Webpack在将代码编译为bundle.js时不会引发任何错误，但是当我尝试使用node bundle.js运行bundle.js时，它说: TypeError:mg._Schema不是构造函数

So VSCode suggests me my class, and IntellIsense works. But it seems there is no implementation of the class. Webpack doesn´t throw any errors when compiling my code to bundle.js but when i try to run my bundle.js with node bundle.js it says: TypeError: mg._Schema is not a constructor

推荐答案

您将需要两件事:

1. 用声明文件扩展mongoose的类型定义.
2. 添加功能，以便模块匹配其新定义.

1. Extend the type definition of mongoose with a declaration file.
2. Add functionality so the module matches its new definition.

mongoose.d.ts

mongoose.d.ts

创建一个声明文件(*.d.ts)并将其包含在您的项目中.

Create a declaration file (*.d.ts) and include it in your project.

import * as mg from 'mongoose';

declare module 'mongoose' {
  export class _Schema extends mg.Schema {
    constructor(definition?: mg.SchemaDefinition, options?: mg.SchemaOptions);
  }

  export function _limitedRequest(schema: mg.Schema, options: number): void;
}

mongoose-instance.ts

mongoose-instance.ts

添加您刚刚声明的功能.

Add the functionality you just declared.

import mg from 'mongoose';

mg._Schema = class extends mg.Schema {
    constructor(definition?: mg.SchemaDefinition, options?: mg.SchemaOptions) {
        super(definition, options)
        this.addData()
    }
    private addData() {
        //do stuff
    }
}

mg._limitedRequest = function _limitedRequest(schema: mg.Schema, options = 200) {
  schema.pre("find", function (next) {
      this.limit(options)
      next()
  })
}

export default mg;

consumer.ts

consumer.ts

从现在开始，使用本地版本的mongoose.

From now on, use your local version of mongoose.

import mongoose from '../path/to/mongoose-instance';

console.log(mongoose._Schema);

如果遇到与默认导入有关的任何问题，请确保在tsconfig.json中启用以下两个标志:allowSyntheticDefaultImports和esModuleInterop.

If you encounter any problems related to default imports, make sure to enable these two flags in your tsconfig.json: allowSyntheticDefaultImports and esModuleInterop.

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