esbuild 0.12.28

v0.12.28

on Node.js NPM

Fix U+30FB and U+FF65 in identifier names in ES5 vs. ES6+ (#1599)

The ES6 specification caused two code points that were previously valid in identifier names in ES5 to no longer be valid in identifier names in ES6+. The two code points are:

• U+30FB i.e. KATAKANA MIDDLE DOT i.e. ・
• U+FF65 i.e. HALFWIDTH KATAKANA MIDDLE DOT i.e. ･

This means that using ES6+ parsing rules will fail to parse some valid ES5 code, and generating valid ES5 code may fail to be parsed using ES6+ parsing rules. For example, esbuild would previously fail to parse x.y･ even though it's valid ES5 code (since it's not valid ES6+ code) and esbuild could generate {y･:x} when minifying even though it's not valid ES6+ code (since it's valid ES5 code). This problem is the result of my incorrect assumption that ES6 is a superset of ES5.

As of this release, esbuild will now parse a superset of ES5 and ES6+ and will now quote identifier names when possible if it's not considered to be a valid identifier name in either ES5 or ES6+. In other words, a union of ES5 and ES6 rules is used for parsing and the intersection of ES5 and ES6 rules is used for printing.

Fix ++ and -- on class private fields when used with big integers (#1600)

Previously when esbuild lowered class private fields (e.g. #foo) to older JavaScript syntax, the transform of the ++ and -- was not correct if the value is a big integer such as 123n. The transform in esbuild is similar to Babel's transform which has the same problem. Specifically, the code was transformed into code that either adds or subtracts the number 1 and 123n + 1 throws an exception in JavaScript. This problem has been fixed so this should now work fine starting with this release.