Migrating from Bun

// ❌ Bun
const text = await Bun.file("./data.txt").text();
const json = await Bun.file("./data.json").json();
await Bun.write("./out.txt", "data");

// ✅ esrun
import { file, write } from "runtime:fs";

const text = await file("./data.txt").text();
const json = await file("./data.json").json();
await write("./out.txt", "data");

// ❌ Bun
const proc = Bun.spawn(["git", "rev-parse", "HEAD"]);
const text = await new Response(proc.stdout).text();

// ✅ esrun
import { Command } from "runtime:system";

const { stdout } = await new Command("git", {
  args: ["rev-parse", "HEAD"],
}).output();

const text = new TextDecoder().decode(stdout).trim();

// ❌ Bun
const key = Bun.hash(data);
const digest = new Bun.CryptoHasher("sha256").update("data").digest("hex");
const stored = await Bun.password.hash(input);

// ✅ esrun
import { hash, Hasher, password } from "runtime:hashing";

const key = hash("xxhash64", data);
const digest = new Hasher("sha256").update("data").digest("hex");
const stored = await password.hash(input);

// ❌ Bun
Bun.serve({ fetch(req) { req.cookies.set("theme", "dark"); return new Response("ok"); } });
const cookie = new Bun.Cookie("sid", id, { httpOnly: true });

// ✅ esrun
import { serve, Cookie } from "runtime:http";

serve((req) => { req.cookies.set("theme", "dark"); return new Response("ok"); });
const cookie = new Cookie("sid", id, { httpOnly: true });

// ❌ Bun
import { AsyncLocalStorage } from "node:async_hooks";
const store = new AsyncLocalStorage();
store.run({ tenant }, () => handle(req));
store.getStore().tenant;

// ✅ esrun
import { createContext } from "runtime:context";
const store = createContext({ name: "request" });
store.run({ tenant }, () => handle(req));
store.get().tenant;

// ❌ Bun
process.memoryUsage().heapUsed;
process.cpuUsage().user;      // microseconds
import { heapStats } from "bun:jsc";

// ✅ esrun
import { memoryUsage, cpuTime, uptime } from "runtime:process";
import { metrics, subscribe } from "runtime:diagnostics";

memoryUsage().heapUsed;
cpuTime();                    // milliseconds, this agent's thread
metrics().gc.pauseMs.p99;     // needs --allow-diagnostics

// ❌ Bun
const thumb = await Bun.file("photo.jpg").image()
  .resize(400, 400, { fit: "inside" })
  .webp({ quality: 80 })
  .bytes();
await new Bun.Image(upload).resize(1600).write("public/large.avif");

// ✅ esrun
import { Image } from "runtime:images";
import { file } from "runtime:fs";

const thumb = await new Image(file("photo.jpg"))
  .resize(400, 400, { fit: "inside" })
  .webp({ quality: 80 })
  .bytes();
await new Image(upload).resize(1600).avif().write(file("public/large.avif"));