In the next version of Bun
— Jarred Sumner (@jarredsumner) December 10, 2023
Bun.write() will automatically create parent directories if they do not exist pic.twitter.com/jNgjZ5LAtl
{% /raw %} ## Rewritten IO for `Bun.file` The internals of `Bun.file` on Linux have been rewritten to use epoll instead of io_uring, which improves compatibility in Docker and cloud hosts like Vercel and Google Cloud Run. This addresses 11 issues related to `EBADF` when using `Bun.file`:  The impetus for this change was Docker disabled io_uring by default in November 2023. ### Bun.write() and Bun.file().text() gets 3x faster under concurrent load Along the way, we improved the performance of reading and writing files concurrently using Bun.file() and Bun.write(). Reading: ```js ❯ N=100 hyperfine "bun ./read.js" "bun-1.0.15 read.js" --warmup=20 Benchmark 1: bun ./read.js Time (mean ± σ): 40.9 ms ± 2.9 ms [User: 27.6 ms, System: 181.7 ms] Range (min … max): 37.1 ms … 48.3 ms 73 runs Benchmark 2: bun-1.0.15 read.js Time (mean ± σ): 134.5 ms ± 19.0 ms [User: 24.8 ms, System: 82.5 ms] Range (min … max): 98.8 ms … 161.2 ms 23 runs Summary bun ./read.js ran 3.29 ± 0.52 times faster than bun-1.0.15 read.js ``` Writing: ```ts ❯ N=100 hyperfine "bun ./write.js" "bun-1.0.15 write.js" --warmup=20 Benchmark 1: bun ./write.js Time (mean ± σ): 35.0 ms ± 8.0 ms [User: 13.0 ms, System: 364.6 ms] Range (min … max): 25.7 ms … 71.5 ms 83 runs Benchmark 2: bun-1.0.15 write.js Time (mean ± σ): 134.7 ms ± 13.6 ms [User: 23.6 ms, System: 193.3 ms] Range (min … max): 117.8 ms … 171.2 ms 23 runs Summary bun ./write.js ran 3.85 ± 0.96 times faster than bun-1.0.15 write.js ``` read.js: ```ts const promises = new Array(parseInt(process.env.N || "20")); for (let i = 0; i < promises.length; i++) { promises[i] = Bun.file("out.log." + i).text(); } await Promise.all(promises); ``` write.js: ```ts const toPipe = new Blob(["abc".repeat(1_000_000)]); const promises = new Array(parseInt(process.env.N || "20")); for (let i = 0; i < promises.length; i++) { promises[i] = Bun.write("out.log." + i, toPipe); } await Promise.all(promises); ``` ### Fixed: Bun.stdin.text() incomplete reads Previously, `Bun.stdin.text()` would sometimes not return all of the data from stdin. ```ts import { stdin } from "bun"; console.log(await stdin.text()); ``` ```shell $ echo "Hello, world!" | bun script.ts ``` Previously, sometimes it would print nothing: ```sh ``` Now, it prints the full input: ```sh Hello, world! ``` ## `napi_create_object` gets 2.5x faster {% raw %}You run
— Bun (@bunjavascript) December 7, 2023
await Bun.write(“/dir-doesnt-exist/file.txt”, “abc”)
Do you expect the function to throw because “dir-doesn’t-exist” doesn’t exist?
{% /raw %} ## `expect` and `expect.extend` in `--preload` Previously, `expect` was scoped to the indivdual test file, which would break `expect.extend` if it was called in a shared file. This is now fixed, and you can now use a shared file containing your custom matchers such as. ```ts#custom-matchers.ts import { expect } from "bun:test"; // Based off of from Jest's example documentation // https://jestjs.io/docs/expect#expectextendmatchers function toBeWithinRange(actual, floor, ceiling) { const pass = actual >= floor && actual <= ceiling; return { pass, message: () => "expected " + this.utils.printReceived(actual) + " to " + (pass ? "not " : "") + "be within range " + this.utils.printExpected(`${floor} - ${ceiling}`), }; } expect.extend({ toBeWithinRange, }); ``` Then configure `bunfig.toml` to load them during testing, ```toml#bunfig.toml test.preload = "./custom-matchers.ts" ``` and run `bun test`: ```ts#example.test.ts import { expect, test } from "bun:test"; test("example", () => { expect(1234).toBeWithinRange(1000, 2000); }); ``` ```diff example.test.ts: -TypeError: expect.extend is not a function. (In 'expect.extend({ - toBeWithinRange -})', 'expect.extend' is undefined) - at /custom-matchers.ts:21:1 +✓ example [1.31ms] ``` You can also use `expect()` outside of `test` callbacks. ```diff -error: This function can only be used in a test. - at /custom-matchers.ts:21:1 ``` ## Fixed: module resolution bug with `"imports"` in `package.json` Packages can declare a list of internal-only imports in their `package.json` file, which Bun will use to resolve imports. This is useful for avoiding exposing internal files to users. ```json { "name": "my-package", "imports": { "my-package": "./dist/index.js" } } ``` These imports are prefixed with `#`. ```js import { foo } from "#my-package"; ``` This can also be used to rewrite imports from other packages. For example, if you wanted to rewrite all imports from `async-hooks` to `#async-hooks`, you could do: ```json { "name": "my-package", "imports": { "async-hooks": "async-hooks" } } ``` Then, it will load the `async-hooks` package: ```js import { foo } from "#async-hooks"; ``` Except, there was a bug that caused aliasing packages this way to not work in Bun. This has been fixed. Notable packages this bug impacted: - **Astro v4** - **`p-limit`** ## Fixed: holey arrays appearing as undefined in console.log Previously, holey arrays would appear as `undefined` in `console.log`. This has been fixed. ```js console.log([1, , 3]); ``` Now: ```js [ 1, empty item, 3 ] ``` Previously: ```js [1, undefined, 3]; ``` ## Fixed: file: URLs in createRequire() that contain spaces Previously, `createRequire()` would throw an error when passed a `file:` URL which contained an unescaped space. This has been fixed. ```js import { createRequire } from "node:module"; const require = createRequire(import.meta.url); require("file:///Users/jarred/My%20Folder/script.js"); ``` Thanks to [@paperclover](https://github.com/paperclover) for fixing this. ## Fixed: console.log was omiting the `length` property sometimes Sometimes, `console.log` would omit the `length` property of an object. This has been fixed. ```js console.log({ length: 1, a: 1 }); ``` Previously, it would print: ``` { a: 1 } ``` Now, it prints: ``` { length: 1, a: 1, } ``` ## Fixed: transpiler inconsistentcy with jsx key after spread The following input would behave differently in Bun versus in TypeScript: ```jsx const obj = {}; console.log(, ); ``` This has been fixed, thanks to [@rhyzx](https://github.com/rhyzx). ## Fixed: `console.log("%d", value)` bug A bug causing `%d` to not handle non-numeric values correctly has been fixed. ```js console.log("%d", "1"); ``` Previously, it would print: ``` 0 ``` Now, it prints: ``` 1 ``` ## Fixed: Syntax highlighter template string handling In the previous version of Bun, we added syntax-highlighting to the code shown in error messages, but it has a bug that caused some template strings to crash the highlighter. This has been fixed. ## Fixed: jest.fn(jest.fn()) crash A crash when calling `jest.fn(jest.fn(() => {}))` has been fixed, thanks to [@Hanassagi](https://github.com/Hanassagi). ## Thanks to 16 contributors! We're always excited to welcome new contributors to Bun. 6 new contributors made their first contribution in this release. - [@mkayander](https://github.com/@mkayander) made their first contribution in [#7453](https://github.com/oven-sh/bun/pull/7453) - [@asilvas](https://github.com/@asilvas) made their first contribution in [#7446](https://github.com/oven-sh/bun/pull/7446) - [@annervisser](https://github.com/@annervisser) made their first contribution in [#7289](https://github.com/oven-sh/bun/pull/7289) - [@sstephant](https://github.com/@sstephant) made their first contribution in [#7477](https://github.com/oven-sh/bun/pull/7477) - [@DaleSeo](https://github.com/@DaleSeo) made their first contribution in [#7532](https://github.com/oven-sh/bun/pull/7532) - [@bradymadden97](https://github.com/@bradymadden97) made their first contribution in [#7529](https://github.com/oven-sh/bun/pull/7529) - [@dfaio](https://github.com/@dfaio) made their first contribution in [#7542](https://github.com/oven-sh/bun/pull/7542) Thanks to the 16 contributors who made this release possible: - [@annervisser](https://github.com/annervisser) - [@asilvas](https://github.com/asilvas) - [@bradymadden97](https://github.com/bradymadden97) - [@DaleSeo](https://github.com/DaleSeo) - [@dfaio](https://github.com/dfaio) - [@dylan-conway](https://github.com/dylan) - [@Hanaasagi](https://github.com/Hanaasagi) - [@ImBIOS](https://github.com/ImBIOS) - [@Jarred-Sumner](https://github.com/Jarred) - [@jerome-benoit](https://github.com/jerome) - [@mkayander](https://github.com/mkayander) - [@otgerrogla](https://github.com/otgerrogla) - [@paperclover](https://github.com/paperclover) - [@rhyzx](https://github.com/rhyzx) - [@RiskyMH](https://github.com/RiskyMH) - [@sirenkovladd](https://github.com/sirenkovladd) - [@sstephant](https://github.com/sstephant)in the next version of Bun
— Jarred Sumner (@jarredsumner) December 5, 2023
napi_create_object gets 2.5x faster pic.twitter.com/lXyj6koceT