Tabular Data Pipelines: Converting CSV to Structured JSON in Web Apps

Published 2026-08-01 | Author: Sarah Connor | Category: tutorials

How CSV header detection, type inference, delimiter parsing, and streaming parsers convert flat spreadsheet data into hierarchical JSON schemas.

## Bridging Legacy Spreadsheets with Modern JSON APIs Comma-Separated Values (CSV) remains the standard export format for financial spreadsheets and database dumps, whereas web applications communicate via structured JSON objects. Converting CSV to JSON involves more than simply splitting lines by commas—it requires delimiter handling, quote escaping, and automatic data type coercion. --- ## 1. Handling CSV Edge Cases - **Custom Delimiters**: Supporting commas (`,`), semicolons (`;`), tabs (`\t`), and pipes (`|`). - **Quoted Fields with Internal Delimiters**: A field containing `"New York, NY"` must not be split at the internal comma. - **Type Coercion**: Automatically parsing string values like `"42"` into numbers and `"true"` into booleans. --- ## 2. TypeScript CSV to JSON Parser Implementation ```typescript export function parseCSVToJSON(csvText: string, delimiter = ','): Record[] { const lines = csvText.trim().split(/\r?\n/); if (lines.length < 2) return []; const headers = lines[0].split(delimiter).map(h => h.replace(/^"|"$/g, '').trim()); return lines.slice(1).map(line => { const values = line.split(delimiter).map(v => v.replace(/^"|"$/g, '').trim()); const row: Record = {}; headers.forEach((h, idx) => { const val = values[idx] || ''; row[h] = !isNaN(Number(val)) && val !== '' ? Number(val) : val; }); return row; }); } ```

Tabular Data Pipelines: Converting CSV to Structured JSON in Web Apps

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