Obtain values from the AWS Parameter store with Typescript/node

parameterStore.ts

import { SSM } from "aws-sdk";

const getParameterWorker = async (name:string, decrypt:boolean) : Promise<string> => {
    const ssm = new SSM();
    const result = await ssm
    .getParameter({ Name: name, WithDecryption: decrypt })
    .promise();
    return result.Parameter.Value;
}

export const getParameter = async (name:string) : Promise<string> => {
    return getParameterWorker(name,false);
}

export const getEncryptedParameter = async (name:string) : Promise<string> => {
    return getParameterWorker(name,true);
}

If using serverless you'll need the following IAM

provider:
  region: us-west-2
  accountId: XXXXXXXXXX
  iamRoleStatements:
    - Effect: Allow
      Action: 
        - ssm:GetParameter
      Resource:
        - "arn:aws:ssm:${self:provider.region}:${self:provider.accountId}:parameter/TWILIO*"

Works like a charm! Only in my case I decided to modify it a bit, because my use case is I'm retrieving an SSM parameter value in my cdk script, so in my stack I actually need to create the SSM with the region info like new SSM({ region: this.region }). So I updated it slightly to pass in the SSM client to the function instead as in this example.