I am trying to read an SNS Topic that I stored into a file to query the key values. I keep getting an error:

`testRegex.ts:8:45 - error TS2339: Property 'Records' does not exist on type 'string'.

8 const messageText = JSON.parse(data.Records[0].Sns.Message.message);`

The value in the file DOES exist, but something in the readFile() Module is not allowing the string to be converted in JSON.parse().

Here is the code:

import { readFileSync, promises as fsPromises, readFile } from "fs";

readFile("./regex", "utf-8", (err, data) => {
  if (err) {
    console.error(err);
    return;
  }
  const messageText = JSON.parse(data.Records[0].Sns.Message.message);
  console.log(messageText);
});

Data file format and content (regex):

"Records": [
        {
            "EventSource": "aws:sns",
            "EventVersion": "1.0",
            "EventSubscriptionArn": "arn:aws:sns:us-west-2:123456789012:Opsgenie_Alert_Messages_Prod:11g22y11-dd9e-4e40-a17c-d1111111111",
            "Sns": {
                "Type": "Notification",
                "MessageId": "5885272a-55d5-5c91-bf15-5b0253cab710",
                "TopicArn": "arn:aws:sns:us-west-2:123456789012:Opsgenie_Alert_Messages_Prod",
                "Subject": null,
                "Message": "{\"integrationName\":\"AmazonSNS (Outgoing)\",\"alert\":{\"alertId\":\"182374692817346129837\",\"message\":\"[AS] foobar_TEST on 10.00.0.00 has late Task Agent Jobs on TSTSRVR - Notification 8.9.3.11\",\"tags\":[\"alerts_as8\"],\"tinyId\":\"20000\",\"source\":\"35.00.000.0\",\"entity\":\"\",\"alias\":\"0baba525-5c10-41f0-b480-1293c2900c53_late_120\",\"createdAt\":1672348639658,\"updatedAt\":1672348640358000000,\"username\":\"Alert API\",\"userFullName\":\"Alert API\",\"description\":\"Last Status Message (from DB):\\nProcessing queue subscription...\\n\\nScheduled Start Time:\\n2022-12-29T08:00:00\\n\\nLast Heartbeat Time:\\n2022-12-29T10:00:00.293\\n\\nHelpful links: \\n[Graylog](http://graylog.companyname.local/)\\n\\nThese links rely on naming conventions and might be incorrect:\\n\\n[Log File](http://graylog.companyname.local/search?q=institution:fakesiteuri_TEST AND TA_Log_File:Notification\\2022\-12%5=%%C-29\-08_00_23.log&rangetype=relative&relative=17777)\\n\\n[Site]( https://www.companyname.com/some_TEST/Logon.aspx?nosso= )\\n\\n\\n{AgentURL=taskagent://TSTTSK50:7640,Version=8.9.3.11, Database=DB_TESTsites\":{\"AgentURL\":\"taskagent://TSTTSK50:7640\",\"AstraVersion\":\"8.9.3.11\",\"Database\":\"l}}",
                "Timestamp": "2022-12-29T21:17:19.913Z",
                "SignatureVersion": "1",
                "Signature": "<SomeValueHere>",
                "SigningCertUrl": "https:*.pem",
                "UnsubscribeUrl": "https://sns.us-west-2.amazonaws.com/?Action=Unsubscribe&SubscriptionArn=arn:aws:sns:us-west-:Opsgenie_Alert_Messages_Prod:",
                "MessageAttributes": {}
            }
        }
    ]

I tried querying the object in the first node (data) and it prints out. When I try to add the second node (Records[0]) it errors out on me.

I expect to be able to query the object with JSON.parse() and store the values into a variable.

CodePudding user response：

Your code fails even before trying to parse the JSON.

How about something like this?

import { readFileSync, promises as fsPromises, readFile } from 'fs';

readFile('./regex', 'utf-8', (err, data) => { 
  if(err) { 
    console.error(err); 
  } else { 
    const parsedData = JSON.parse(data);     
    const messageText = parsedData.Records[0].Sns.Message.message;     
    console.log(messageText);
  }
});

CodePudding user response：

Thanks to Matj and Ol234 for putting me on the right track!

I was missing the step to parse the outer JSON String (regex file) prior to parsing the inner JSON String (Records[0].Sns.Message).

Here is the working code:

import { readFileSync, promises as fsPromises, readFile } from 'fs';

readFile('./regex', 'utf-8', (err, data) => {
  if (err) {
    console.error(err);
    return;
  }
  // Parse outer/parent JSON String
  const rawData = JSON.parse(data);
  //Parse Inner JSON String "Message"
  const messageJson = JSON.parse(rawData.Records[0].Sns.Message);
  //Log value of tinyId to console
  console.log(messageJson.alert.tinyId);
});