How to Convert CSV to JSON in JavaScript

The simple idea

CSV to JSON conversion starts with one rule: the first row usually becomes the object keys. Every following row becomes one JSON object.

CSV:

sku,name,price
A-100,Keyboard,49.99
B-200,Mouse,24.5

JSON:

[
  { "sku": "A-100", "name": "Keyboard", "price": 49.99 },
  { "sku": "B-200", "name": "Mouse", "price": 24.5 }
]

You can test this instantly with the CSV to JSON Converter, then reuse the output in JavaScript.

Basic JavaScript parser

For very simple CSV without quoted commas, this works:

function csvToJson(csv) {
  const rows = csv.trim().split("\n");
  const headers = rows[0].split(",").map((header) => header.trim());

  return rows.slice(1).map((row) => {
    const values = row.split(",");
    return headers.reduce((record, header, index) => {
      record[header] = values[index]?.trim() ?? "";
      return record;
    }, {});
  });
}

This version is useful for clean internal data, but it fails when a cell contains a comma inside quotes.

Handling quoted commas

Real CSV often contains values like this:

id,note
1,"Imported from New York, USA"

A production-ready parser needs a small state machine that tracks whether the current character is inside quotes. The CSV to JSON Converter uses this kind of approach so commas inside quoted fields remain part of the same value.

Type casting

CSV stores everything as text. JSON can represent strings, numbers, booleans, and null values. A useful converter can turn:

"42" -> 42
"true" -> true
"" -> null

This is helpful when you need JSON for API payloads, seed data, tests, or front-end fixtures.

Browser-safe workflow

If you are debugging a small export, paste it into the CSV to JSON Converter, inspect the output, then copy the JSON into your JavaScript file. This is faster than writing a parser every time and avoids uploading private CSV files.

FAQ

Should I use a library?

Use a library for large files, streaming imports, or complex edge cases. For small browser-side conversions, a local converter is often faster.

Can JavaScript parse Excel CSV?

Yes, as long as the exported file is plain CSV text. Check whether the delimiter is comma, semicolon, or tab.

What is the safest output shape?

An array of objects is usually the safest output because each row keeps the same named keys from the header row.