evanw/esbuild v0.12.11

on GitHub

Enable faster synchronous transforms with the JS API by default (#1000)

Currently the synchronous JavaScript API calls transformSync and buildSync spawn a new child process on every call. This is due to limitations with node's child_process API. Doing this means transformSync and buildSync are much slower than transform and build, which share the same child process across calls.

This release improves the performance of transformSync and buildSync by up to 20x. It enables a hack where node's worker_threads API and atomics are used to block the main thread while asynchronous communication with a single long-lived child process happens in a worker. Previously this was only enabled when the ESBUILD_WORKER_THREADS environment variable was set to 1. But this experiment has been available for a while (since version 0.9.6) without any reported issues. Now this hack will be enabled by default. It can be disabled by setting ESBUILD_WORKER_THREADS to 0 before running node.

Fix nested output directories with WebAssembly on Windows (#1399)

Many functions in Go's standard library have a bug where they do not work on Windows when using Go with WebAssembly. This is a long-standing bug and is a fault with the design of the standard library, so it's unlikely to be fixed. Basically Go's standard library is designed to bake "Windows or not" decision into the compiled executable, but WebAssembly is platform-independent which makes "Windows or not" is a run-time decision instead of a compile-time decision. Oops.

I have been working around this by trying to avoid using path-related functions in the Go standard library and doing all path manipulation by myself instead. This involved completely replacing Go's path/filepath library. However, I missed the os.MkdirAll function which is also does path manipulation but is outside of the path/filepath package. This meant that nested output directories failed to be created on Windows, which caused a build error. This problem only affected the esbuild-wasm package.

This release manually reimplements nested output directory creation to work around this bug in the Go standard library. So nested output directories should now work on Windows with the esbuild-wasm package.