evanw/esbuild v0.15.17

on GitHub

Search for missing source map code on the file system (#2711)

Source maps are JSON files that map from compiled code back to the original code. They provide the original source code using two arrays: sources (required) and sourcesContent (optional). When bundling is enabled, esbuild is able to bundle code with source maps that was compiled by other tools (e.g. with Webpack) and emit source maps that map all the way back to the original code (e.g. before Webpack compiled it).

Previously if the input source maps omitted the optional sourcesContent array, esbuild would use null for the source content in the source map that it generates (since the source content isn't available). However, sometimes the original source code is actually still present on the file system. With this release, esbuild will now try to find the original source code using the path in the sources array and will use that instead of null if it was found.

Fix parsing bug with TypeScript infer and extends (#2712)

This release fixes a bug where esbuild incorrectly failed to parse valid TypeScript code that nests extends inside infer inside extends, such as in the example below:

type A<T> = {};
type B = {} extends infer T extends {} ? A<T> : never;

TypeScript code that does this should now be parsed correctly.

Use WebAssembly.instantiateStreaming if available (#1036, #1900)

Currently the WebAssembly version of esbuild uses fetch to download esbuild.wasm and then WebAssembly.instantiate to compile it. There is a newer API called WebAssembly.instantiateStreaming that both downloads and compiles at the same time, which can be a performance improvement if both downloading and compiling are slow. With this release, esbuild now attempts to use WebAssembly.instantiateStreaming and falls back to the original approach if that fails.

The implementation for this builds on a PR by @lbwa.

Preserve Webpack comments inside constructor calls (#2439)

This improves the use of esbuild as a faster TypeScript-to-JavaScript frontend for Webpack, which has special magic comments inside new Worker() expressions that affect Webpack's behavior.