* refactor: simplify token context structure
* add benchmark
* perf: return a sub-state on tokenizer lookahead
* Update packages/babel-parser/src/tokenizer/index.js
Co-authored-by: Brian Ng <bng412@gmail.com>
* Update packages/babel-parser/src/tokenizer/index.js
Co-authored-by: Brian Ng <bng412@gmail.com>
* remove irrelevant comment
* fix: guard curPosition with isLookahead
* add test cases
Co-authored-by: Brian Ng <bng412@gmail.com>