Bun is a fast, all-in-one toolkit for installing, bundling, running and testing JavaScript & TypeScript. To install: `npm i -g bun`
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ALT Line chart titled "51.4M Monthly Bun downloads." Downloads grow from 7.2M in October 2025 to 51.4M in October 2026, climbing fastest in the last few months. Four events are marked: Bun 1.3 in October 2025, Joined Anthropic in December, Rust rewrite in May, and Bun 1.4 in August. A label reads "+57% since 1.4."
ALT The Bun logo and the heading "$ bun test: Improved Vitest compatibility", above a Vitest test file with three lines highlighted and numbered: // @vitest-environment jsdom import { expect, test, vi } from "vitest"; import { track } from "./analytics"; import { toast } from "./toast"; vi.mock("./analytics"); test("toast hides after 3s", async () => { vi.useFakeTimers(); toast("Saved!"); expect(track).toHaveBeenCalled(); await vi.advanceTimersByTimeAsync(3000); expect(document.body.innerHTML).toBe(""); }); The highlighted lines: 1. DOM environments: the "@vitest-environment jsdom" comment 2. Automocks: vi.mock("./analytics") with no factory 3. Async fake timers: await vi.advanceTimersByTimeAsync(3000)
ALT Chart titled "Bun AoT, ahead-of-time compilation". An Express API on SQLite: 3 middlewares, bearer auth, 4 SQL queries, 2.3 KB of JSON per request. A line chart of requests per second over the first 3 seconds from a cold start: Bun AoT is near full speed at once and settles at 14,200; Bun climbs for about a second to 14,200; Node.js reaches 7,700. Peak memory: Bun AoT 51 MB, Bun 87 MB, Node.js 138 MB. CPU per request: Bun AoT 70 Β΅s, Bun 82 Β΅s, Node.js 150 Β΅s. Caption: As fast, 14% less CPU, 41% less memory than Bun.
ALT claude.ai CI typecheck: tsc β bun check 69 S faster 21s bun check 77% less time 4.3x faster tsc 90 s median time to type-check all of claude.ai in Cl β’ tsc is TypeScript 7 (native) β’ Oct 2026
