perf(estree/tokens): serialize tokens to compact JSON

[overlookmotel]

Perf optimization to converting tokens to ESTree JSON. Previously we serialized to pretty-printed JSON. Instead use compact JSON - it's just passed to JSON.parse on JS side, so there's no need for whitespace.

[overlookmotel]

• perf(estree/tokens): use strings from AST for identifier tokens #19744 : 2 dependent PRs (#19735 , #19796 )
• refactor(estree/tokens): add TokenType type #19789
• feat(estree): add IS_COMPACT const to Formatter trait #19787
• feat(estree): expose buffer and formatter of serializers #19773
• perf(estree): use CodeBuffer::print_strs_array to reduce bounds checks #19766
• feat(data_structures): add CodeBuffer::print_strs_array #19760
• perf(estree): use CodeBuffer::print_indent #19727
• perf(estree/tokens): serialize tokens while visiting AST #19726
• perf(estree/tokens): serialize with ESTree not serde #19725
• feat(estree): oxc_estree crate export config and formatter types #19724
• refactor(estree/tokens): convert tokens spans before AST spans #19723
• refactor(estree/tokens): simplify code #19722
• perf(estree/tokens): do not branch on presence of override twice #19721
• refactor(estree/tokens): move logic for excluding legacy identifiers into visitor #19720
• perf(estree/tokens): replace hash map with Vec #19718
• perf(estree/tokens): replace multiple hash sets into a single hash map #19716
• refactor(estree/tokens): replace stored token when re-lexing #19698
• perf(parser): remove branches from finish_next_inner #19695
• perf(parser): remove const generic param from finish_next_inner #19684
• feat(parser): add LexerConfig::TOKENS_METHOD_IS_STATIC const #19683
• docs(parser): improve doc comments for ParserConfig and LexerConfig #19682
• refactor(estree/tokens): use wildcard import for AST types #19681
• test(estree): ESTree conformance check files with hashbangs #19680
• fix(estree/tokens): reverse field order of regex object in tokens #19679
• perf(estree/tokens): serialize tokens to compact JSON #19572 👈 (View in Graphite)
• ci(benchmarks): correct comment #19650
• perf(parser/tokens): pre-allocate capacity for tokens #19543
• fix(estree/tokens): generate tokens for files with BOM #19535
• refactor(estree/tokens): combine collect_token_context into to_estree_tokens_json #19534
• refactor(estree): reorder tokens code #19533
• refactor(coverage): standardize ESTree tokens testing functions #19532
• perf(linter/plugins): remove typescript from bundle #19531
• docs(linter/plugins): correct doc comments for initTokens #19530
• refactor(linter/plugins): combine functions for getting tokens #19529
• ci(benchmarks): benchmark parser with tokens and ESTree tokens conversion #19649
• perf(linter/plugins): use Oxc tokens in plugins #19498
• test(estree/tokens): do not skip tokens conformance tests for files with hashbangs #19643
• fix(estree): fix tokens for JSX #19524
• perf(parser): introduce ParserConfig #19637
• feat(parser,estree,coverage): collect tokens in parser and convert to ESTree format #19497
• feat(coverage): add estree token conformance scaffolding #19496
• fix(tasks/coverage): bring back acorn-jsx estree testing #19516 : 1 other dependent PR (#19515 )
• chore(submodules): update submodule SHAs to latest commits #19518
• main

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[codspeed-hq]

Merging this PR will improve performance by 29.22%

⚡ 1 improved benchmark
✅ 51 untouched benchmarks
⏩ 3 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	estree_tokens[checker.ts]	322.6 ms	249.7 ms	+29.22%

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_{Comparing om/02-20-perf_estree_tokens_serialize_tokens_to_compact_json (112333d) with om/02-23-ci_benchmarks_correct_comment (e0476b5)²}

Footnotes

1. 3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on om/02-23-ci_benchmarks_correct_comment (ee9c4aa) during the generation of this report, so e66bff1 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[Copilot]

Pull request overview

This PR aims to optimize performance by converting ESTree tokens to compact JSON instead of pretty-printed JSON. The optimization is based on the fact that the JSON is immediately parsed on the JavaScript side, so whitespace formatting serves no purpose and only increases the payload size.

Changes:

• Modified to_estree_tokens_json to use serde_json::to_string (compact) instead of serde_json::to_string_pretty
• Added new to_estree_tokens_pretty_json function for generating pretty-printed JSON when needed
• Updated test coverage code to use the new pretty-printed function

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated no comments.

File	Description
crates/oxc_estree_tokens/src/lib.rs	Refactored to_estree_tokens_json to use compact JSON serialization and added to_estree_tokens_pretty_json for pretty-printed output
tasks/coverage/src/tools.rs	Updated test coverage functions to import and call to_estree_tokens_pretty_json instead of to_estree_tokens_json