Building a Pivot Table in Vanilla JavaScript: Cross-Tabs, Measures, and Totals That Don't Lie

Building a Pivot Table in Vanilla JavaScript: Cross-Tabs, Measures, and Totals That Don't Lie

"Pivot table" sounds like a feature you buy. It's the thing spreadsheets are famous for and the thing every BI tool puts on its pricing page, and when a stakeholder asks for one on a dashboard the instinct is to reach for a grid library or export the data to Excel and let them do it themselves. The Pivot Table snippet does the whole job — cross-tabulation, switchable measures, row totals, column totals, grand total — in about forty lines of plain JavaScript, and the interesting part isn't the rendering. It's that a handful of those lines encode a decision most implementations get subtly wrong. Here it is live — switch the measure and watch every number in the grid, including the totals, recompute: Grab the code, or open the full editor with live HTML/CSS/JS panels: Pivot Table on FWD Tools . The snippet is plain HTML, CSS, and JavaScript, but the same editor has one-click export buttons for React , Vue , Angular , and React + Tailwind if you'd rather drop it into a…