[SOLVED] Unable to execute method inside AWS Lambda function. TypeError this.method is not a function


This Content is from Stack Overflow. Question asked by adamwright000

I’ve recently switched to writing my AWS Lambda functions in TypeScript from vanillaJS as I use Angular so thought it’d be better for better muscle memory, but am running into the following error when trying to execute a method inside the lambda function.

"errorType": "TypeError",
"errorMessage": "this.test is not a function",
"stack": [
    "TypeError: this.test is not a function",
    "    at Runtime.lambda [as handler] (/var/task/index.js:17:249)",
    "    at Runtime.handleOnceNonStreaming (file:///var/runtime/index.mjs:1028:29)"


How do I fix this? Have tried a few different ways but to no avail so far. P.S, I don’t use Serverless framework or anything similar. This is just me writing and uploading as ZIP with AWS CLI. Function executes without this problem.

import { Context, APIGatewayProxyResult, APIGatewayEvent } from 'aws-lambda';

class Index {
    constructor() { }

    test() {
        return "test"

    public async lambda(event: APIGatewayProxyResult, context: Context): Promise<any> {

        return {
            statusCode: 200,
            body: this.test()

export const index = new Index()
export const handler = index.lambda


Fixed thanks to GitHub Co-Pilot suggestion (and btw, anyone that doesn’t have this, $10 per month is a no-brainer. It’s fantastic)

Needed to bind this to lambda function in my constructor.

constructor() {
    this.lambda = this.lambda.bind(this)

This Question was asked in StackOverflow by adamwright000 and Answered by adamwright000 It is licensed under the terms of CC BY-SA 2.5. - CC BY-SA 3.0. - CC BY-SA 4.0.

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