@evokegroup/aws

AWS utilities

Requires NodeJS 18+

Class: LambdaEvent

Properties

Property	Type	Description
event	object	The event data from Lambda

Class: ApiGatewayEvent

extends LambdaEvent

Properties

Property	Type	Description
headers	object	The event headers
stageVariables	object	The stage variables sent into the event by API Gateway

Methods

getBody()

Returns the event request body.

setBody(value)

Overwrite the event request body.

Parameter	Type	Default	Description
value	*		The body value. Will be stringified.

getBodyJSON()

Returns the event request body as JSON or Error if the data cannot be parsed.

isJsonRequest()

Returns true if the Content-Type header is set to application/json

getHeader(name)

Gets a header by a case-insensitive name.

Parameter	Type	Default	Description
name	string		The case-insensitive header name

setHeader(name, value)

Sets a header.

Parameter	Type	Default	Description
name	string		The case-insensitive header name
value	string		The header value

getStage()

Gets the stage sent by API Gateway

getStageVariable(name)

Gets a stage variable by name. Returns null if not found.

Parameter	Type	Default	Description
name	string		The stage variable name

setStageVariable(name, value)

Overrides a stage variable.

Parameter	Type	Default	Description
name	string		The stage variable name
value	string		The stage variable value

Class: Config

Base class for configurations classes that can pass their configuration values via an object

Methods

init(config = this)

Initializes the configuration properties.

set(config = {})

Sets properties.

initProperty(name, value)

Initializes a single property

Parameter	Type	Description
name	string	The property name
value	*	The default property value

getTypedEnvValueOrDefault(value, defaultValue)

Attempts to convert value to the defaultValue type. If defaultValue is a function, value will be passed as the argument and the result will be returned.

Parameter	Type	Description
value	*	The value
defaultValue	*	The default typed value to fallback on

Class: EnvironmentConfig

extends Config

Base class for configurations classes using environment variables (process.env)

Class: LambdaConfig

extends EnvironmentConfig

Base class for configurations classes within a Lambda function

constructor(event)

Parameters	Type	Default	Description
event	EvokeAws.LambdaEvent, object		The event data passed to the Lambda function

const { LambdaConfig, SuccessResponse } = require('@evokegroup/aws');

class MyConfig extends LambdaConfig {
  site = null;
  environment = null;

  constructor(event) {
    super(event); 
    this.init();
  }
}

export const handler = async (event) => {
  return new Promise((resolve, reject) => {
    const config = new MyConfig(event);
    // do stuff
    resolve(SuccessResponse.json());
  });
};

Properties

event

The EvokeAws.LambdaEvent created from the event data passed to the function

Class: ApiGatewayConfig

extends EnvironmentConfig

Base class for configurations classes within a Lambda function being exexuted via API Gateway and using stage variables

Class: LambdaResponse

A basic Lambda response object.

{
  statusCode: 200,
  headers: {
    "Access-Control-Allow-Origin": "*"
  },
  body: "Hello world",
  isBase64Encoded: false
}

constructor(object)

Parameter	Type	Default	Description
statusCode	number	200	The HTTP status code
headers	object	{ "Access-Control-Allow-Origin": "*" }	The response headers. These headers will be merged with the default headers.
body	string		The response body
isBase64Encoded	boolean	false	The body is base64 encoded

// Return a base64 encoded Buffer
import { LambdaResponse } from '@evokegroup/aws';
export const handler = async (event) => {
  return new Promise((resolve, reject) => {
    resolve(LambdaResponse.json({ body: Buffer.from('data', 'ascii'), isBase64Encoded: true }));
  });
}

Methods

serialize()

Serializes the response.

toJSON()

See serialize.

Class: JsonResponse

extends LambdaResponse

Base class for JSON-based responses.

{
  statusCode: 200,
  headers: {
    "Access-Control-Allow-Origin": "*",
    "Content-Type": "application/json"
  },
  body: "{\"success\":true,\"message\":\"OK\",\"data\":{}}",
  isBase64Encoded: false
}

constructor(object)

Parameter	Type	Default	Description
statusCode	number	200	The HTTP status code
headers	object	{ "Access-Control-Allow-Origin": "*" }	The response headers. These headers will be merged with the default headers.
message	string	""
data	object	null

Class: SuccessResponse

extends JsonResponse

Creates a JsonResponse with a default statusCode = 200 and body success = true.

constructor(object)

Parameter	Type	Default	Description
statusCode	number	400	The HTTP status code
headers	object	{ "Content-Type": "application/json" }	See EvokeAws.LambdaResponse
message	string	""	The response message
data	object	null	An object to send back in the response

const { SuccessResponse } = require('@evokegroup/aws');

export const handler = async (event) => {
  return new Promise((resolve, reject) => {
    resolve(SuccessResponse.json());
  });
};

Class: ErrorResponse

extends JsonResponse

Creates a JsonResponse with a default statusCode = 400 and body success = false.

{
  statusCode: 400,
  headers: {
    "Access-Control-Allow-Origin": "*",
    "Content-Type": "application/json"
  },
  body: "{\"success\":false,\"message\":\"An error has occurred.\",\"data\":null}",
  isBase64Encoded: false
}

constructor(object)

Parameter	Type	Default	Description
statusCode	number	400	The HTTP status code
headers	object	{ "Content-Type": "application/json" }	See EvokeAws.LambdaResponse
message	string	""	The response message
data	object	null	An object to send back in the response
err	object	null	Any error information

const { ErrorResponse } = require('@evokegroup/aws');

export const handler = async (event) => {
  return new Promise((resolve, reject) => {
    resolve(ErrorResponse.json({ statusCode: 403, message: 'Unauthorized' }));
  });
};