JavaScript Playground

Run JavaScript in a Web Worker with built-in CSV parsing, groupBy/sumBy helpers, and Chart.js rendering — the same stack powering modern data dashboards and full-stack analytics apps.

In this workspace

What you get when you open Code Studio.

Run Script

Script editor
Monaco editor with console output and chart images
File explorer
main.js / main.ts plus mounted data files
⌘/Ctrl+Enter
Run the script from the keyboard or toolbar
Cheatsheet insert
Drop common snippets into the editor in one click

Your JavaScript playgrounds

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No JavaScript playgrounds yet

Opens in the Code Studio workspace.

Starter template

// sales.csv loads from the Data panel
const rows = loadCSV("sales.csv");
console.log("Loaded", rows.length, "rows");
console.log(rows[0]);

const byRegion = groupBy(rows, "region");
for (const [region, group] of Object.entries(byRegion)) {
 console.log(region, "→ revenue:", sumBy(group, "revenue"));
}

await renderChart({
 type: "bar",
 data: {
 labels: Object.keys(byRegion),
 datasets: [{
 label: "Revenue",
 data: Object.values(byRegion).map((group) => sumBy(group, "revenue")),
 backgroundColor: ["#3b82f6", "#f59e0b", "#10b981", "#ef4444"],
 }],
 },
 options: { plugins: { title: { display: true, text: "Revenue by Region", color: "#cbd5e1" } } },
});

What you'll learn

✓Custom visualizations
✓JSON transforms
✓Dashboard logic
✓Web analytics prototyping

Starter template

// sales.csv loads from the Data panel const rows = loadCSV("sales.csv"); console.log("Loaded", rows.length, "rows"); console.log(rows[0]); const byRegion = groupBy(rows, "region"); for (const [region, group] of Object.entries(byRegion)) { console.log(region, "→ revenue:", sumBy(group, "revenue")); } await renderChart({ type: "bar", data: { labels: Object.keys(byRegion), datasets: [{ label: "Revenue", data: Object.values(byRegion).map((group) => sumBy(group, "revenue")), backgroundColor: ["#3b82f6", "#f59e0b", "#10b981", "#ef4444"], }], }, options: { plugins: { title: { display: true, text: "Revenue by Region", color: "#cbd5e1" } } }, });