c9fcdf3e80
SnakeYAML 2.3 has [a bug](https://bitbucket.org/snakeyaml/snakeyaml/issues/1098) where it crashes with an `IndexOutOfBoundsException` when a Unicode surrogate pair (e.g. an emoji) straddles the 1024 character internal buffer boundary. This happens because the high surrogate can end up as the last character in the data window, and the reader tries to read the low surrogate past the end of the buffer. This caused languages that extract YAML, most notably JavaScript and Actions, to fail when the codebase contained a YAML file with an emoji at an unlucky position in the file.
JavaScript extractor
This directory contains the source code of the JavaScript extractor. The extractor depends on various libraries that are not currently bundled with the source code, so at present it cannot be built in isolation.
The extractor consists of a parser for the latest version of ECMAScript, including a few proposed and historic extensions (see src/com/semmle/jcorn), classes for representing JavaScript and TypeScript ASTs (src/com/semmle/js/ast and src/com/semmle/ts/ast), and various other bits of functionality. Historically, the main entry point of the JavaScript extractor has been com.semmle.js.extractor.Main. However, this class is slowly being phased out in favour of com.semmle.js.extractor.AutoBuild, which is the entry point used by CodeQL.
License
Like the CodeQL queries, the JavaScript extractor is licensed under the MIT License by GitHub. Some code is derived from other projects, whose licenses are noted in other LICENSE-*.md files in this folder.