Middy，回调类型

Question

我试图在Lambda调用中使用TyepScript witn Middy。我的代码之一是：

// My types definition
import BodyRequestType from 'types';

// some code

async function myFunction (
  event: { body: BodyRequestType },
  callback: ??? <--
): Promise<void> {
  // my code
  return callback(null, {
    statusCode: 200,
    body: JSON.stringify(data)
  });
}

export const handler = middy(myFunction);

我试着用：

import { Callback } from 'aws-lambda'
// then...
callback: Callback

但是我在middy(myFunction)上得到了这个错误

TS2345: Argument of type '(event: { body: BodyRequestType; }, callback: Callback<any>) => Promise<void>' is not assignable to 
parameter of type 'AsyncHandler<Context>'.
Type '(event: { body: BodyRequestType; }, callback: Callback<any>) => Promise<void>'
is not assignable to type '(event: any, context: Context, callback: Callback<any>) => void'.
Types of parameters 'callback'and 'context' are incompatible.
Type 'Context' is not assignable to type 'Callback<any>'.
Type 'Context' provides no match for the signature '(error?: string | Error | null | undefined, result?: any): void'.

我应该在callback参数myFunction中使用哪种类型？

Answer 1

问题是第二个参数应该是其签名中的Context类型，而不是回调。

由于需要上下文，所以只需将context和callback分别设置为第2、第3参数，如下所示：

import { Context, Callback } from 'aws-lambda';


async function myFunction (
  event: { body: BodyRequestType },
  context: Context,
  callback: Callback 
) {
  // ...
}