d3-csv-loading

name	d3-csv-loading
description	Load and parse CSV data with D3.js v6 using d3.csv() and d3.autoType for local file serving.

Loading CSV Data with D3.js v6

d3.csv()

const data = await d3.csv("data/stock-descriptions.csv", d3.autoType);

• d3.autoType auto-converts numeric strings to numbers.
• For local files, must be served via HTTP (use python3 -m http.server).

Handling CSV with Quoted Fields

D3's CSV parser handles RFC 4180 (quoted fields with commas inside). The stock-descriptions.csv has columns:

• ,ticker,sector,full name,marketCap,fullTimeEmployees,longBusinessSummary,country,website,...
• First column is an unnamed index column.

Key Pattern: Inline Data

When local file serving is not guaranteed, embed data as a JS variable:

const DATA = [...];  // pre-processed JSON array

This avoids CORS/fetch issues when opening HTML files directly with file://.