How to properly extract specific fields from API response data in Node.js

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1

I’m working with Node.js and making requests to a financial API. The API returns JSON data in an array format, but I’m having trouble accessing specific values from the response.

Here’s my current setup:

const https = require('https');
const express = require('express');
const app = express();

app.post('/financial-data', function(req, res) {
    const requestOptions = {
        method: 'GET',
        hostname: 'api.example.com',
        path: '/v1/company-data/MSFT',
        headers: {
            'Authorization': 'Bearer your-token-here',
            'Content-Type': 'application/json'
        }
    };

    const apiRequest = https.request(requestOptions, function(apiResponse) {
        let dataChunks = [];
        
        apiResponse.on('data', function(dataChunk) {
            console.log(dataChunk.toString('utf-8')[15]);
            dataChunks.push(dataChunk);
        });
        
        apiResponse.on('end', function() {
            const responseBody = Buffer.concat(dataChunks);
            // Need to process this data properly
        });
    });
    
    apiRequest.end();
});

The response looks like this:

[25 items
0: {
  "reportDate": "2023-06-30",
  "companySymbol": "MSFT",
  "submissionDate": "2023-07-25",
  "totalRevenue": 211915000000,
  "operatingIncome": 88523000000,
  "totalAssets": 411976000000,
  "currentLiabilities": 95082000000,
  "totalEquity": 238268000000,
  "longTermDebt": 47032000000
}]

When I try to access a specific field like totalEquity using dataChunk[0], it just gives me individual characters instead of the actual data object. I expected something like dataChunk[0]['totalEquity'] would work, but it doesn’t. What’s the correct way to parse and access these specific values from the API response?

2

parse the json first b4 accessing fields. use JSON.parse(responseBody.toString()) then access array with parsedData[0].totalEquity. you’re getting individual chars cause dataChunk is raw buffer data.

3

Been there with financial APIs - they’re a pain to work with manually. Everyone’s right about the JSON parsing issue, but there’s a bigger problem.

You’re building an entire Node.js server just to fetch and transform API data. That’s way too much boilerplate for something simple.

I’ve handled tons of financial data integrations. Writing custom Node.js code for every API connection gets messy fast. You end up maintaining authentication, error handling, data transformation - all that infrastructure stuff.

Skip the https requests and buffer concatenation headaches. Automate this whole flow instead. Set up the API connection once, define your data extraction rules, and let it run automatically.

I’ve used this approach for extracting specific fields from complex financial APIs. Just map the response fields you need (totalEquity, totalRevenue) and the platform handles all the parsing and data flow.

No more debugging buffer issues or maintaining server code. Just clean, reliable data extraction.

Check out Latenode for API automation: https://latenode.com

4

You’re trying to parse incomplete data chunks instead of waiting for the full response. Each chunk is just a piece of the complete JSON string. That’s why console.log(dataChunk.toString('utf-8')[15]) only shows individual characters - you don’t have the full JSON object yet.

Move your parsing logic to the ‘end’ event handler where you’ve got the complete response. After const responseBody = Buffer.concat(dataChunks);, convert and parse it: const jsonData = JSON.parse(responseBody.toString()); const equity = jsonData[0].totalEquity;.

I’ve hit this same problem with financial APIs - you can’t parse JSON from streaming responses until you’ve received the complete payload.

5

You’re trying to access array indices on raw buffer data before converting it to a JavaScript object. The dataChunk is binary data, not parsed JSON. You need to concat all chunks first, then parse the complete response. After your Buffer.concat(dataChunks) line, add const parsedResponse = JSON.parse(responseBody.toString()) to convert the buffer to a string and parse the JSON. Then access specific fields with parsedResponse[0].totalEquity or whatever field you need. I’ve done this same mistake with streaming API responses - you’ve got to wait for all data chunks before trying to parse the complete JSON.