run2-stock-data-wrangling

name	run2_stock-data-wrangling
description	Robust data cleaning and formatting for financial datasets in D3.js.

Stock Data Wrangling

Ensuring data consistency between individual files and the summary CSV.

Robust ETF Detection

ETFs often have missing sector and marketCap. Explicitly label them to apply specific logic (uniform sizing, no tooltip).

const processed = rawData.map(d => {
    const marketCap = d.marketCap ? parseFloat(d.marketCap) : null;
    const isETF = isNaN(marketCap) || !marketCap || d.sector === "" || d.sector === "ETF";
    return {
        ...d,
        marketCap,
        isETF,
        sector: isETF ? "ETF" : d.sector
    };
});

Precise Market Cap Formatting

Formatting numbers to "1.64T" or "150B" using fixed precision.

function formatCurrency(val) {
    if (!val) return "N/A";
    const trillion = 1e12;
    const billion = 1e9;
    const million = 1e6;
    
    if (val >= trillion) return (val / trillion).toFixed(2) + "T";
    if (val >= billion) return (val / billion).toFixed(2) + "B";
    if (val >= million) return (val / million).toFixed(2) + "M";
    return val.toLocaleString();
}