Jeremy Nguyen jeremy-code

Constructing new Array from TypedArray

Benchmarks

Benchmark	Test	Status	Error	Ops/s	Average	Mean batch	Median	p95	Std deviation	95% RME	Batches	Operations	Measured	Relative
Constructing new Array from TypedArray	Array.from	Success		1,133	882.9 µs	882.9 µs	879.7 µs	893.7 µs	17.34 µs	0.323%	142	9,088	8.024 s	93.91% slower
Constructing new Array from TypedArray	Array.from({ length })	Success		580.4	1.723 ms	1.723 ms	1.634 ms	1.815 ms	488.5 µs	4.599%	146	4,672	8.049 s	96.88% slower

const decodingTable = [
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60,
  61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
  14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26,
  27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45,
  46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
];

Benchmarks - Constructing a stream from Uint8Array

https://jsbenchmark.com/#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

Web APIs/CSS/JavaScript features supported by Chrome and Firefox, but not Safari

Ever been curious what features are supported by the main browsers except Safari? As of October 2026, the count is 429 Web API features, 95 CSS features, and 8 JavaScript features (Of course, this includes features that are preview-only by Firefox, so this list isn't really meaningful for determining feature availability for actual users). Code is provided at index.ts using data from @mdn/browser-compat-data.

Web APIs

Feature	Chrome	Firefox
AuthenticatorAttestationResponse.getPublicKey.algorit

`libheif.py` port configuration

For my port of libheif, I decided to do it similar to how emscripten also handled ".cc" files for harfbuzz, where the srcs and cflags are inlined based on what CMake would've generated.

The above is the port file that was used to generate the initial build. After that, I just used the following command to get the list of paths.

jq \
  --raw-output \
 --arg pwd "$PWD/" \

zod toZod preprocess/transform behavior

import * as z from "zod";

import { Readable } from "node:stream";

const readableStreamSchema = z.toZod<ReadableStream<unknown>>()(
  z.instanceof(ReadableStream),
);

Emscripten Compiler Options

ASSERTIONS
STACK_OVERFLOW_CHECK
CHECK_NULL_WRITES
VERBOSE
INVOKE_RUN
EXIT_RUNTIME
STACK_SIZE
MALLOC

TextDecoderStream vs TextDecoder Benchmark

https://jsbm.dev/DBsfstlxUQexn

TextDecoderStream Ops/s: 2,565 Average run time: 0.39 ms

TextDecoder Ops/s: 7,597

	import * as z from "zod";
	//#region src/generated/zod.gen.ts
	/**
	* Additional entity definition for AccountRole
	*/
	const accountRoleSchema = z.object({
	color: z.string(),
	id: z.string(),
	name: z.string()
	});

	import os
	import shutil

	from tools import shared, utils

	URL = 'https://github.com/AOMediaCodec/libavif'
	DESCRIPTION = 'libavif is a library for encoding and decoding .avif files'
	LICENSE = 'BSD 2-Clause License'

	TAG = '1.4.2'