evanw/esbuild v0.8.10

on GitHub

Fix parsing of conditional types in TypeScript (#541)

Conditional types in TypeScript take the form A extends B ? C : D. Parsing of conditional types in esbuild was incorrect. The ? can only follow an extends clause but esbuild didn't require the extends clause, which potentially led to build failures or miscompilation. The parsing for this syntax has been fixed and should now match the behavior of the TypeScript compiler. This fix was contributed by @rtsao.

Ignore comments for character frequency analysis (#543)

Character frequency analysis is used to derive the order of minified names for better gzip compression. The idea is to prefer using the most-used characters in the non-symbol parts of the document (keywords, strings, etc.) over characters that are less-used or absent. This is a very slight win, and is only approximate based on the input text instead of the output text because otherwise it would require minifying twice.

Right now comments are included in this character frequency histogram. This is not a correctness issue but it does mean that documents with the same code but different comments may be minified to different output files. This release fixes this difference by removing comments from the character frequency histogram.

Add an option to ignore tree-shaking annotations (#458)

Tree shaking is the term the JavaScript community uses for dead code elimination, a common compiler optimization that automatically removes unreachable code. Since JavaScript is a dynamic language, identifying unused code is sometimes very difficult for a compiler, so the community has developed certain annotations to help tell compilers what code should be considered unused. Currently there two forms of tree-shaking annotations that esbuild supports: inline /* @__PURE__ */ comments before function calls and the sideEffects field in package.json.

These annotations can be problematic because the compiler depends completely on developers for accuracy and the annotations are occasionally incorrect. The sideEffects field is particularly error-prone because by default it causes all files in your package to be considered dead code if no imports are used. If you add a new file containing side effects and forget to update that field, your package will break when people try to bundle it.

This release adds a new flag --tree-shaking=ignore-annotations to allow you to bundle code that contains incorrect tree-shaking annotations with esbuild. An example of such code is @tensorflow/tfjs. Ideally the --tree-shaking=ignore-annotations flag is only a temporary workaround. You should report these issues to the maintainer of the package to get them fixed since they will trip up other people too.

Add support for absolute baseUrl paths in tsconfig.json files

Previously esbuild always joined the baseUrl path to the end of the current directory path. However, if the baseUrl was an absolute path, that would end up including the current directory path twice. This situation could arise internally in certain cases involving multiple tsconfig.json files and extends fields even if the tsconfig.json files themselves didn't have absolute paths. Absolute paths are now not modified and should work correctly.

Fix crash for modules that do module.exports = null (#532)

The code generated by esbuild would crash at run-time if a module overwrote module.exports with null or undefined. This has been fixed and no longer crashes.